[854]*854OPINION
CARPENETI, Justice.
I. INTRODUCTION
An employee was injured three times over the span of five months while working as a pipe fitter for his employer. The employee fell twice, injuring his lumbar and cervical spine and his hip, and also complained of sharp pain in his right hand that doctors attributed to his work. After he was laid off from his Alaska job, the employee returned to his home in California, where he began chiropractic treatment for his spinal injuries. His employer initially paid benefits without an award; it filed a notice of controversion after its experts reported that the employee was medically stable and no longer in need of treatment. The Alaska Workers' Compensation Board held a hearing on the employee's claim for medical and disability benefits and decided that the employee was entitled to limited chiropractic benefits, denied the rest of his claims, and awarded him limited attorney's fees. The employee, through his attorney, also requested a reemployment eligibility evaluation. The Reemployment Benefits Administrator (RBA) determined that the employee was eligible for an evaluation. The employer appealed the RBA's decision to the board; the board found that the employee had filed his request too late and denied it.
The employee appealed both decisions to the superior court. The superior court affirmed the board's decisions in most respects. We reverse the board's denial of temporary total disability benefits, its denial of reimbursement for travel costs, and its reversal of the RBA's decision, and affirm the board's decisions on all remaining issues.
II. FACTS AND PROCEEDINGS
Rory Burke was employed as a pipe fitter on the Alaska pipeline for many years, working about half the year in Alaska and spending the rest of the year at his home in California. Burke worked for Houston NANA, L.L.C.1 off and on for two years. In June 2001 he fell when he stepped in a hole that was covered with wood chips while he was carrying an cighty-pound load down a hill near Glenallen. He strained his hip and shoulder but did not take time off work or file a report of occupational injury form.2 In mid-August he again injured himself when he stepped into a hole created when a large rock was moved. Finally, during the night of October 16, severe cramping and numbness in his right hand woke him up. He attributed the hand pain to work he had been doing, lifting a heavy beam and bolting heavy Teflon pads in place and operating an impact gun. He went to an urgent care clinic in Fairbanks on October 25, 2001, complaining of neck pain for the previous three months and cramping in his right hand. The doctor at the clinic diagnosed right epicondylitis3 and cervical neck strain, wrote that the conditions were work-related, and limited Burke to lifting no more than forty pounds. Burke signed a report of occupational injury on October 830, 2001. He was laid off work the same day as part of a reduction in force. Burke returned to California in early November. Houston NANA paid workers' compensation benefits without an award effective November 19, 2001.
On November 19, 2001, Burke saw Dr. Joel Taatjes, a chiropractor in Petaluma, California, for treatment related to his work injuries. At that time, Dr. Taatjes completed a California workers' compensation form entitled "Doctor's First Report of Occupational Injury." Dr. Taatjes's report estimated that Burke's treatment would require approximately thirty visits over a twelve- to sixteen-week period, or between two to three visits per week. However, Burke received almost [855]*855daily treatments from Dr. Taatjes for about three weeks and then treatments two or three times a week for another thirty weeks or so. During the course of his treatment of Burke, Dr. Taaties sent Houston NANA progress reports on forms from the State of California Division of Workers' Compensation. Each form included a place for the doctor to detail the treatment plan, including the methods, frequency, and duration of planned treatments. Dr. Taatjes described the therapy he was conducting, but did not specify the number or duration of treatments. He simply indicated "decreasing fre-queney as the patient's status improves."
Houston NANA arranged for a panel of doctors to conduct an independent medical evaluation (IME) on March 19, 2002. The panel consisted of a chiropractor, Dr. Willat, and an orthopedic surgeon, Dr. Ramsey. Both doctors examined Burke and reviewed his medical records. Both agreed that Burke was medically stable, at least with respect to his spinal injuries. Dr. Ramsey diagnosed Burke with mild right carpal tunnel syndrome and indicated that Burke's work had caused his neck, back, and carpal tunnel problems on a more-probable-than-not basis. In Dr. Ramsey's opinion, Burke had a slight permanent partial impairment but could return to his work as a pipe fitter as long as he was not required to use vibrating equipment on a sustained basis because of the carpal tunnel problems. Dr. Ramsey rated Burke as having a two percent whole person permanent impairment as a result of the carpal tunnel syndrome. Dr. Ramsey thought that Burke might need future medical care for his carpal tunnel syndrome, although he did not see a need for immediate medical care. Both Drs. Ramsey and Willat felt that further passive chiropractic treatments like the ones Burke was receiving from Dr. Taatjes were not necessary.
After the IME reports noted that Burke might have carpal tunnel syndrome, Dr. Taatjes referred Burke to a neurosurgeon, Dr. Guy Corkill, Dr. Taatjes evidently believed that the hand complaints were related to Burke's neck injuries and wanted Dr. Cor-kill to identify the reason for the continuing pain. Dr. Corkill examined Burke on May 28, 2002, diagnosed cervical disk disease, and referred Burke to Dr. Marcia Luisi, a specialist in physical medicine and rehabilitation, for electrodiagnostic studies. Dr. Luisi examined Burke on June 18, 2002, and performed nerve conduction studies to determine the cause of his right hand complaints. Dr. Luisi concluded that Burke had moderate right carpal tunnel syndrome and that the electrodiagnostic studies showed no indication of cervical radiculopathy. Following Dr. Luisi's report, Dr. Corkill recommended that Burke get a wrist splint. On August 23, 2002, Dr. Corkill advised Burke to have surgery for his carpal tunnel syndrome. Dr. James Glynn, an orthopedic surgeon, evaluated Burke on October 2, 2002, and recommended right carpal tunnel release. Burke had the surgery on November 18, 2002.
Dr. Taatjes referred Burke to Dr. Don Davis, a chiropractic neurologist, for a "permanent and stationary evaluation" on September 19, 2002. Based on his examination of Burke and his review of the medical ree-ords, Dr. Davis believed that Burke was permanent and stationary, except for his right hand. He stated that in his opinion, Burke's chiropractic treatment up to that time had been appropriate and should continue on an "exacerbation basis." Dr. Davis did not feel that Burke could return to his work as a pipe fitter, noting restrictions on his ability to bend, lift, carry, push, pull, and squat. Dr. Taatjes adopted the report as his own.
Houston NANA filed a notice of controversion on May 8, 2002, based on the IME reports. It controverted temporary total disability (TTD) benefits after May 1, 2002, and all further chiropractic care and physical therapy. The controversion noted that the IME doctors had determined that Burke was medically stable as of March 19, 2002; it also stated that medical care for Burke's right carpal tunnel condition "as outlined in Dr. Ramsey's EME report" would be covered. A copy of the controversion notice was sent to Dr. Taatjes.
Burke filed a workers' compensation claim on June 26, 2002. In his claim, he requested TTD benefits from May 2, 2002 through medical stability, permanent partial impairment benefits, medical costs related to Dr. [856]*856Taatjes's care, transportation costs, penalties, interest, and attorney's fees. Houston NANA filed its answer to the claim on July 15, 2002.
Burke requested that the Alaska Workers' Compensation Board (the board) order a see-ond independent medical evaluation (SIME) to address issues of treatment, functional capacity, and medical stability. Houston NANA agreed that an SIME was appropriate in Burke's case, so the board ordered one. Two SIME physicians evaluated Burke: Dr. Marvin Bloom, an orthopedic surgeon, and Dr. Seott Calzaretta, a chiropractor. Dr. Bloom stated that Burke would not improve further without cervical fusion surgery and that even with neck surgery, Burke would likely not be able to return to his former work as a pipe fitter. Dr. Bloom did not feel that further chiropractic treatment was indicated; he believed that Burke was medically stable as of December 2002. Dr. Bloom rated Burke as having an eight percent whole person impairment related to his spinal injuries. He did not specifically discuss the carpal tunnel syndrome in the conclusions in his report.
Dr. Calzaretta thought that limited chiropractic treatment was still appropriate in Burke's case but that the frequency of treatment needed to be decreased to one to two times a month rather than two to three times a week. Dr. Calzaretta agreed with Dr. Willat that Burke was medically stable with respect to his spinal injuries as of March 19, 2002. Dr. Calzaretta felt that Burke could return to work as a pipe fitter as long as he was "precluded from repetitive pneumatic activity with his right hand." He also thought that Burke should lift no more than forty pounds overhead to prevent possible injuries to his neck and back.
The board held a hearing on Burke's claim on September 4, 2008. Burke testified in person, and Dr. Taatjes testified telephoni-cally. Burke argued that his treatment with Dr. Taatjies was reasonable and necessary, even though it was in excess of the treatment limits, because he had multiple injuries but continued to work and because the chiropractic care helped him avoid surgery and expensive pain medication. He also asserted that Houston NANA had waived its argument that the treatment plan was excessive because it did not specifically object to the form of the plan in its controversion notice: The notice stated only that the care was not necessary. Burke also contended that his carpal tunnel syndrome was not medically stable from May 2, 2002 through November 17, 2002, and that he should receive TTD benefits for that period of time.
Houston NANA called Burke's carpal tunnel argument a "red herring" and asserted that Burke was medically stable as of March 19, 2002. Houston NANA also argued that Burke had not met his burden of showing that his chiropractic care was reasonable and necessary, especially in light of the treatment standards set out in board regulations. In addition, it argued that Dr. Taatjes's treatment plans were inadequate in that they did not specify the frequency or duration of treatment.
The board issued its decision on October 3, 2003. It found that Burke was medically stable as of March 19, 2002, and was therefore not eligible for TTD benefits from March 19, 2002, until November 19, 2002, the day after he had surgery for right carpal tunnel syndrome. The board stated that, in accordance with Grove v. Alaska Construction and Erectors,4 it did not have the authority to award medical benefits in excess of the regulatory standards because Dr. Taatjes had not filed a treatment plan that conformed to the requirements of AS 23.30.095(c)5 The board rejected Burke's [857]*857argument that Houston NANA had waived its objection to the form of the treatment plan when it controverted chiropractic treatment. The board awarded payment for one chiropractor visit per month from May 2002 to November 2002 because Drs. Calzaretta and Davis thought that some chiropractic care was still indicated and one visit per month was within the regulatory standards. It denied Burke's request for reimbursement of his costs to attend the hearing, finding that his in-person testimony was not necessary for the limited issue on which he prevailed. The board also decided that only a limited fee award was appropriate and ordered Burke's attorney to submit another affidavit, segregating the time he spent working on the chiropractic care issue. Burke filed a timely appeal in the superior court, alleging numerous errors in the board's decision.
Before the board issued a decision on the TTD claim, Burke, through his attorney, wrote the Reemployment Benefits Administrator to request a reemployment eligibility evaluation. Acknowledging that the request was late, Burke set out "unusual and extenuating circumstances" to justify his tardy application. The unusual and extenuating circumstances were that (1) Burke suffered a series of injuries, not just a single injury, in his employment; (2) time loss benefits did not begin until November 19, 2001, more than thirty days after the last injury; (8) Burke thought he would be able to return to his work as a pipe fitter; and (4) no doctor had predicted within the first ninety days that Burke would not be able to return to his job at the time of injury. Burke also urged the RBA to reject any argument that the request for an eligibility evaluation was untimely under the board's discovery rule because, according to Burke, the plain meaning of the statute only required the RBA to make a determination of unusual and extenuating circumstances excusing a late-filed request. In response to Burke's request, Houston NANA wrote the RBA, arguing that Burke's request should be denied. On November 12, 2008, the RBA explained his interpretation of the statutory deadlines, determined that Burke had unusual and extenuating circumstances that justified his late request, and decided that Burke was entitled to an evaluation for reemployment benefits. The RBA noted that in the first ninety days after giving his employer notice of his injury, "there was no indication that rehabilitation might be needed." Houston NANA appealed the RBA's decision to the board. The board held a hearing on the reemployment benefits issue on March 10, 2004.
In its April 14, 2004 decision on the reemployment question, the board decided that the RBA had abused his discretion in finding that Burke was entitled to an eligibility evaluation. The board declared that it had a long history of applying a discovery rule in considering the statutory ninety-day deadline for applying for a reemployment eligibility evaluation. Under the board's discovery rule, the employee has ninety days from the date he has knowledge of his need for retraining to apply for an eligibility evaluation. The board determined that Burke had notice that he would need retraining at the latest on February 25, 2003, the date of Dr. Bloom's SIME report. Because Burke's request was made in September, it was deemed untimely; the board therefore reversed the RBA's decision and denied and dismissed Burke's request for an eligibility evaluation. The board did not review the RBA's determination that Burke had unusual and extenuating cireum-stances excusing his late-filed request, nor did it make any findings related to unusual and extenuating cireumstances.
Rather than file a second appeal, Burke asked the superior court to amend his points on appeal to include the issues raised in the board's reemployment benefits decision. The court did so after receiving no opposition [858]*858from Houston NANA. The superior court affirmed the board's decision in all respects, except for its award of attorney's fees; the court remanded the case to the board for a redetermination of the fee award. The parties subsequently settled the fee issue, and the board approved the settlement. Burke then moved the superior court for entry of a final judgment; this appeal followed.
III. STANDARD OF REVIEW
[1-6] In an appeal of a decision of a superior court acting as an intermediate court of appeal in a workers' compensation case we independently review the board's decision.6 Factual findings are reviewed to see if they are supported by substantial evidence.7 "Substantial evidence is 'such relevant evidence as a reasonable mind might accept as adequate to support a conclusion. "8 For legal questions involving agency expertise or fundamental policy questions, we apply the reasonable basis standard and defer to the agency if its interpretation is reasonable.9 For legal questions involving no agency expertise, we substitute our judgment and apply the rule of law that is most persuasive in light of precedent, reason, and policy.10 We review an agency's application of its regulation to the facts to determine whether the agency's decision was arbitrary, unreasonable, or an abuse of discretion.11 We will find an abuse of discretion when we are left with the definite and firm conviction that a mistake has been made.12
IV. DISCUSSION
A. Burke Is Not Entitled to Chiropractic Care that Exceeds the Regulatory Standards.
Burke argues that the board erred when it ordered Houston NANA to pay for only limited chiropractic treatment. He asserts that (1) Dr. Taatjes filed a treatment plan; (2) the chiropractic care he received was reasonable and necessary; and (8) Houston NANA was barred by estoppel or waiver from arguing that the treatment plan was in any way deficient. Houston NANA responds that the board is legally precluded from awarding benefits in excess of the regulatory treatment standards unless certain conditions are met, and, because Dr. Taatjes did not meet the conditions, it cannot be made to pay for the treatments. Specifically, Houston NANA asserts that Dr. Taatjes was required to file a treatment plan that conformed with the requirements of AS 23.30.095(c) within fourteen days of the beginning of his treatment of Burke; because his treatment plan did not conform to the statutory requirements, Houston NANA cannot be made to pay for treatments in excess of the regulatory standards. It also argues that the frequency standards are not a defense or statutory right that may be waived by an employer.
Alaska Statute 28.30.095(c) contains two provisions detailing the information a health care provider must supply in order to receive payment for continuing and multiple treatments of a similar nature. First, the health care provider or the employee must provide notice of injury and treatment to the board and the employer within fourteen days of commencement of the treatment.13 Next, if a claim is made for a course of continuing and multiple treatments that exceeds the standard treatment frequency, the health care provider is required to give a more detailed treatment plan to both the employer and the employee.14 The treatment plan "must include objectives, modalities, frequen[859]*859cy of treatments, and reasons for the frequency of treatments.15 The statute further specifies that, in the event a treatment plan is not furnished, neither the employer nor the employee can be made to pay for treatments that exceed the frequency standards.16 Finally, the statute requires the board to adopt regulations establishing standards for frequency of treatment.17
The board has adopted a regulation establishing frequency standards that apply to all continuing treatments.18 This regulation provides, in part:
(f) If an injury occurs on or after July 1, 1988, and requires continuing and multiple treatments of a similar nature, the standards for payment for frequency of outpatient treatment for the infury will be as follows. Exeept as provided in (h) of this section, payment for a course of treatment for the injury may not exceed more than three treatments per week for the first month, two treatments per week for the second and third months, one treatment per week for the fourth and fifth months, and one treatment per month for the sixth through twelfth months. Upon request, and in accordance with AS 23.30.095(c), the board will, in its discretion, approve payment for more frequent treatments.
(g) The board will, in its discretion, require the employer to pay for treatments that exceed the frequency standards in (f) of this section only if the board finds that
(1) the written treatment plan was given to the employer and employee within 14 days after treatments began;
(2) the treatments improved or are likely to improve the employee's conditions; and
(8) a preponderance of the medical evidence supports a conclusion that the board's frequency standards are unreasonable considering the nature of the employee's injury.[19]
1. Dr. Taatjes failed to file an adequate treatment plan.
The parties do not dispute that Dr. Taatjes's chiropractic treatments were in excess of the regulatory standards and that he filed some type of treatment plan. The board refused to order Houston NANA to pay for the excess treatments because Dr. Taatjes did not file a treatment plan pursuant to AS 28.30.095. Burke claims that Dr. Taatjes filed a treatment plan that substantially complied with the requirements of AS 28.80.095(c), but he does not elaborate how the forms that Dr. Taatjes filed complied with the statute.
[7] We agree with Houston NANA that Dr. Taatjes's filings do not meet the requirements of AS 23.30.095(c). Dr. Taatjes filed a California workers' compensation form within fourteen days of beginning his treatment of Burke; this form appears to meet the first requirement of AS 23.30.095(c) that the health care provider furnish notice to the board and employer that he will be providing medical care or treatment requiring continuing and multiple treatments of a similar nature. But because Dr. Taaties treated Burke on a more frequent basis than permitted under the applicable regulation, Dr. Taatjes was additionally required to provide a treatment plan to both Burke and Houston NANA that included "objectives, modalities, frequency of treatments, and reasons for the frequency of treatments."20 Dr. Taatjes , failed to do this.
Dr. Taatjes's first filing did not suggest that Dr. Taaties would be treating Burke more frequently than the regulatory standards: It stated that treatment would consist of thirty visits over a twelve- to sixteen-week period. The initial notice described the modalities of treatment but not the objectives. After the initial notice, Dr. Taatjes filed periodic progress reports on forms from the California Division of Workers' Compensation. Had he supplied all of the information [860]*860requested on the forms, they might have contained sufficient information to be considered conforming: The forms ask the provider to specify the methods, frequency, and duration of planned treatments.21 But Dr. Taatjes did not supply all of the requested information; specifically, he did not set out the frequency or duration of the planned treatments. The most he said about frequency of treatment was "decreasing frequency as the patient's status improves." Although Burke presented testimony that Dr. Taaties was not aware of the requirement that he supply a detailed treatment plan, the legislature placed the burden on a health care provider to provide adequate information if he is to be reimbursed for treatments in excess of regulatory standards.22
Burke implicitly argues that it would be inequitable to require Dr. Taatjes to conform to Alaska's statutory requirements because he had no way of knowing that Alaska had limits on the number of treatments. This argument is unavailing, however, because Dr. Taatjes had avenues available to him to comply with the statutory requirements. Although Dr. Taatjes practices in California, the record reflects that his office contacted the Alaska Workers' Compensation Board at one point about the possibility of a lien. In addition, his office apparently discussed possible differences between Alaska and California law with the compensation carrier. Furthermore, Dr. Taatjes could simply have completed the California progress reports completely and accurately.
Burke argues that the record does not contain substantial evidence to support the board's finding that there was no dispute about whether a conforming treatment plan was provided, because he disputed the adequacy of the treatment plan. Burke has never articulated how Dr. Taatjes's filings conformed to or even substantially complied with the statutory requirements for a treatment plan. Before the board, he only argued that Houston NANA was estopped from claiming that the treatment plan was noneon-forming because it had not raised that issue in its notice of controversion. Substantial evidence thus supports the board's conclusion that it was undisputed that Houston NANA did not receive a conforming plan within fourteen days of treatment.
2. Houston NANA is not estopped from raising the adequacy of the treatment plan.
[8] Burke also argues that Houston NANA should be estopped from raising the issue of the noncompliance of Dr. Tasatjes's treatment plan because it did not explicitly do so in its notice of controversion. He contends that if Houston NANA had told Dr. Taatjes of the deficiencies in the plan, Dr. Taatjes could have "stopped or modified his treatments" or "changed his treatment plan to 'conform' to NANA's perceived requirements." Houston NANA responds that failure to follow the statutory requirements for the treatment plan cannot be waived, citing Grove v. Alaska Construction and Erectors.23
The board relied on Grove to deny Burke's claim for chiropractic treatment in excess of the frequency standards. It found that the frequency standards in the regulation could not be waived unless the treatment plan complied with the terms of AS 28.30.095(c), stating that, "(als in Grove, it has not been disputed that the employer was not provided with a treatment plan pursuant to AS 23.30.095 within fourteen days of the treatment."
Burke's argument is similar to the one we rejected in Grove. There, we explicitly rejected the notion that the employer has the burden of objecting to the frequency of an employee's medical treatments.24 Rather, we determined that the legislature placed the burden on the health care provider to pro[861]*861vide a conforming treatment plan if the provider wanted to be paid for visits in excess of the treatment standards.25 We have also held that because the requirement is statutory, the board cannot waive the prerequisite that a treatment plan be furnished within fourteen days of commencement of treatment.26
[91 Although Burke argues that the board had express power to award treatment that exceeded the frequency standards, the board's power is limited to situations in which the statutory requirements of filing a conforming treatment plan are met. To accept Burke's argument that Houston NANA had the duty to tell Dr. Taatjies that the treatment plans did not conform to the statute would place the burden on the employer to object to the frequency of an employee's medical treatments; we explicitly rejected this construction of the statute in Grove.27 Although Dr. Taatjes may have filed some sort of plan, it was not a plan that met the requirements of the statute. Because the statute requires a conforming plan, filing a nonconforming plan does not satisfy the statute.28
3. Rebutting the presumption of com-pensability
Burke also argues that he is entitled to exeess chiropractic care because Houston NANA did not rebut the presumption of compensability. As Burke correctly notes, the presumption of compensability applies to every element of a factual determination.29 He does not, however, explain how the presumption analysis interacts with the frequency standards.
[10] The presumption analysis does not apply to every possible issue in a workers' compensation case. We have previously held the presumption of compensability inapplicable when evaluating a reemployment plan because the parties agreed that the employee's claim was covered by the provisions of the workers' compensation statute and applying the presumption did not "promote the goals of encouraging coverage and prompt benefit payment."30
Here, the board did not use the presumption analysis in evaluating Burke's chiropractic care claim. The presumption analysis might apply to the question whether any chiropractic care was necessary because that would raise the issue whether part of the claim was covered at all. It could also apply if a conforming treatment plan had been filed because the regulation related to excess treatment requires a factual determination about the efficacy of the treatment.31 But we cannot see how the presumption analysis can be used to defeat the explicit statutory provision about frequency of treatment.
[11] Even if the presumption analysis applied, Houston NANA rebutted the presumption of compensability with Dr. Willat's report, which stated that as of March 19, 2002, Burke no longer benefitted from passive chiropractic care of the type he was receiving from Dr. Taatjes. It was then incumbent on Burke to prove that further treatment was reasonable and necessary and that he was entitled to treatment in excess of the frequency standards. The board decided that [862]*862Burke had shown that further chiropractic care was reasonable and necessary, but it limited the frequency of care to the number of visits authorized by regulation because Dr. Taatjes had not filed a treatment plan that conformed to the requirements of AS 23.30.095(c). The board's decision with respect to chiropractic care was correct in all respects.
B. Substantial Evidence Does Not Support the Board's Denial of TTD Benefits from March 19, 2002 Through November 19, 2002.
[12] Burke contends that he is entitled to TTD benefits from March 19, 2002, through November 18, 2002 because his carpal tunnel syndrome was not medically stable as of March 19, 2002, the date that the board determined he had reached medical stability. He alleges that substantial evidence does not support the board's finding of medical stability because evidence in the record shows that Burke was in fact being treated for his carpal tunnel syndrome prior to his carpal tunnel release surgery. In addition, Burke points out that his case is similar to Thoem v. Consumer Electronic Services32 in that by the time the board issued its decision, it knew that the predictive opinions on which it relied to find him medically stable were wrong.33 Houston NANA maintains that substantial evidence in the record supports the board's decision. It points out that both IME physicians stated that Burke was medically stable as of March 19, 2002, and that one of the SIME physicians shared that opinion. It also argues that until the time of surgery, Burke was not being actively treated for carpal tunnel syndrome and that in any event, he was not disabled because of the carpal tunnel syndrome.
In analyzing Burke's claim for TTD, the board found that Burke was entitled to the presumption of compensability that he was still temporarily totally disabled by virtue of his testimony and that of Drs. Davis and Corkill. It then found that Houston NANA had rebutted the presumption through the opinions of Drs. Calzaretta, Willat, and Ramsey that Burke was medically stable as of March 19, 2002.
The board then decided that Burke had not proven his claim. It rejected his argument that his carpal tunnel syndrome was not stable and was disabling from March 19 until his surgery. Its decision was based on two findings: (1) prior to the carpal tunnel surgery, "no treatment was being recommended for the right wrist," and (2) there was "insufficient evidence that the employee was precluded from working ... due to the condition of his wrist." The board also stated that "the medical evidence in the record regarding the employee's wrist indicated that the symptoms were subsiding and that future treatment would only be appropriate if the wrist deteriorated." The board determined that Burke was medically stable as of March 19, 2002, based on the opinions of Drs. Cal-zaretta, Willat, Ramsey, and Bloom and concluded that Houston NANA had overpaid TTD benefits from March 19, 2002, through May 1, 2002.
Because Burke had been receiving TTD benefits, his disability presumptively continued, and Houston NANA had the burden of producing substantial evidence that Burke was no longer disabled.34 We held in Thoeni that a prediction of medical stability that turns out to be incorrect cannot provide substantial evidence to rebut the presumption.35 In Burke's case, as in Thoeni, the board's determination of medical stability was based on opinions that proved to be incorrect. When the board made its decision in Burke's case, it knew that he had in fact undergone the testing and treatment that Houston NANA's expert recommended for treatment of his carpal tunnel syndrome. Houston NANA never controverted this treatment and did not contend that it was unreasonable [863]*863or medically unnecessary.36 Because of this, the opinions of Drs. Ramsey and Willat could not constitute substantial evidence on which the board could rely to find that Burke was medically stable.
The board also relied on the opinions of Drs. Bloom and Calzaretta in its decision. Dr. Bloom expressly stated that, in his opinion, Burke was medically stable as of December 2002. Although Dr. Bloom also said that Burke did not derive any benefit from chiropractic care after March 19, 2002, Burke's chiropractic care was unrelated to his carpal tunnel syndrome. The section of Dr. Calzar-etta's report about medical stability deals only with Burke's spinal complaints, not his carpal tunnel syndrome, and does not constitute substantial evidence to rebut the presumption that Burke's wrist was not medically stable. Dr. Calzaretta describes Burke's carpal tunnel syndrome as "resolving," in contrast to his spinal injuries, which he de-seribes as "maximally improved."
We also hold that Houston NANA did not present substantial evidence to rebut the presumption that Burke was unable to work.37 The only evidence before the board that might have suggested that Burke could work were the opinions of Drs. Ramsey and Calzaretta. But both doctors placed restrictions on Burke's work activities, and the restrictions were directly related to his carpal tunnel syndrome.38 Also, carpal tunnel complaints, along with neck problems, prompted Burke to seek medical attention in Fairbanks in 2001 and caused Dr. Ramsey to give Burke a permanent partial impairment rating. Houston NANA presented no evidence that Burke was able to "earn the wages which the employee was receiving at the time of injury in the same or any other employment."39 Because Houston NANA failed to present substantial evidence to rebut the presumption that Burke continued to be disabled, the board erred in denying his request for TTD benefits.
C. The Board Abused Its Discretion in Denying Burke's Travel Costs.
[18] Burke argues that the board abused its discretion in failing to award him his costs for traveling to Anchorage to attend his workers' compensation hearing in person. He asserts that because the board alone determines witness credibility, in-person testimony can be critical to a claimant's case and claims that there is no way to know in advance of a hearing whether the board will consider the presence of an applicant necessary. He points out the risks that a claimant takes in not appearing in person, such as production of surreptitiously recorded videos. Houston NANA responds that the issues in this case were narrow and related to medical testimony, so Burke should have known before the hearing that his credibility was not an issue.
The board can award "the necessary and reasonable costs relating to the preparation and presentation of the issues upon which the applicant prevailed at the hearing on the claim."40 Included in the costs that the board can award are reasonable travel costs to attend a hearing "if the board finds that the applicant's attendance is necessary."41 We agree with Burke that it is difficult for a claimant to know in advance whether his credibility will be at issue and his presence at the hearing necessary. Houston NANA contends that the issues in this case were only related to medical testimony, but the issues [864]*864the board faced went beyond expert testimony. The board made findings about Burke's ability to continue his work as a pipe fitter, which related to the issue of temporary disability and presumably required testimony from Burke about his work duties and limitations. In addition, had the board determined that Dr. Taatjes had filed an adequate treatment plan, it could have considered Burke's testimony about the efficacy of chiropractic care in deciding whether treatments in excess of the regulatory standards were justified.42 Also, Burke has now prevailed on his temporary disability claim and therefore is eligible for the award of necessary and reasonable costs.43 For these reasons, the board abused its discretion in failing to award Burke his travel costs to attend the hearing in person.
D. The Board Erred in Reversing the Reemployment Benefit Administrator's Decision.
Burke also appeals the board's second decision, in which the board reversed the determination of the Reemployment Benefit Administrator that Burke was entitled to a reemployment eligibility evaluation. Burke maintains that the plain meaning of 8 AAC 45.520 and former AS 28.30.041(c)44 entitle him to an evaluation and that the board's imposition of a discovery rule45 is invalid. He also contends that the board failed in its duty to advise him how to pursue his rights and denied him due process and equal protection.
Houston NANA responds that the discovery rule is a reasonable interpretation of the workers' compensation statute because it furthers the statute's purpose of providing fair and prompt resolution of compensation cases. It asserts that substantial evidence supports the board's determination that Burke knew or should have known that he would not be able to return to his work as a pipe fitter by February 25, 2003, and argues that no unusual or extenuating cireumstances existed under the regulation to excuse Burke's subsequent late filing.
The main issue Burke raises is the application of the following statute and regulation to his case. Former AS 28.80.041(c) provided:
If an employee suffers a compensable injury that may permanently preclude an employee's return to the employee's occupation at the time of injury, the employee or employer may request an eligibility evaluation for reemployment benefits. The employee shall request an eligibility evaluation within 90 days after the employee gives the employer notice of injury unless the administrator determines that the employee has an unusual and extenuating circumstance that prevents the employee from making a timely request.[46]
[865]*865The board adopted a regulation, which became effective July 2, 1998, interpreting "unusual and extenuating circumstance."47 The regulation provides:
(a) An employee requesting an eligibility evaluation for reemployment benefits more than 90 days after giving the employer notice of the injury must submit to the administrator
(1) a written request for the evaluation;
(2) a doctor's prediction that the injury may permanently preclude the employee from returning to the job at the time of injury; and
(3) a written statement explaining the unusual and extenuating circumstances that prevented the employee from timely requesting the eligibility evaluation.
(b) Within 30 days after receiving the information required under (a) of this seetion, the administrator will notify the parties, by certified mail, whether the employee had an unusual and extenuating cireumstance that prevented the employee from making a timely request for an eligibility evaluation. An unusual and extenuating cireumstance exists only if the administrator determines that within the first 90 days after the employee gave the employer notice of the injury
(1) a doctor failed to predict that the employee may be permanently precluded from returning to the job at the time of injury;
(2) the employee did not know that a doctor predicted the employee may be permanently precluded from returning to the job at the time of injury;
(3) the employer accommodated the employee's limitation and continued to employ the employee;
(4) the employee continued to be employed;
(5) the compensability of the injury was controverted and compensability was not resolved; or
(6) the employee's injury was so severe that the employee was physically or mentally prevented from requesting an eligibility evaluation.
(c) Within 10 days after the decision, either party may seek a review of the decision by requesting a hearing under AS 23.30.110.[48]
The board adopted a regulation detailing how an employee should request a reemployment eligibility evaluation at the same time it promulgated the regulation defining unusual and extenuating circumstances.49 This regulation, 8 Alaska Administrative Code 45.510, provides in relevant part:
(a) For injuries occurring on or after July 1, 1988, an employee or an employer may request an eligibility evaluation for reemployment benefits. The request must be in writing, complete in accordance with (b) of this section, and submitted to the administrator.
(b) The administrator will consider a written request for an eligibility evaluation for reemployment benefits if the compens-ability of the injury has not been controverted and if the request is submitted together with
(1) an explanation of the unusual and extenuating cireumstances, as defined in 8 AAC 45.520, for a request that is made more than 90 days after the date the employee gave the employer notice of the injury; and
(2) a physician's prediction that the injury may permanently preclude the employee from returning to the job at time of injury.[50]
Burke did everything that was required by the new regulations. His request for an eligibility evaluation was submitted more than ninety days after he gave notice of his [866]*866injury. Accordingly, he submitted a written request for an evaluation, a doctor's prediction that his work-related injury would permanently preclude him from returning to his work as a pipe fitter, and a statement explaining the unusual and extenuating cireum-stances that prevented him from making a timely request for an eligibility evaluation. No one argues that by January 28, 2002-ninety days after Burke signed the notice of injury-a doctor had predicted that Burke would be unable to return to his job at the time of injury. Indeed, Dr. Taatjes predicted on March 15, 2002, that Burke would "be released to working status" by April 15, 2002. But instead of following its regulations, the board looked back to a prior period to find a rule that barred Burke's request.
Before the two new regulations took effect in 1998, the board had developed through adjudication a discovery rule to be used in considering reemployment eligibility evaluation requests.51 Under the board's discovery rule, an employee who failed to request a reemployment eligibility evaluation within ninety days of providing notice of the injury to the employer as required by former AS 23.30.041(c) was required to request the evaluation within ninety days of the date the employee knew or should have known that he might not be able to return to the occupation at the time of injury.52 This case presents two questions: (1) whether the regulations adopted in 1998, which did not explicitly contain a discovery rule, should be read as continuing the rule despite their silence, and, if not, (2) whether, following the adoption of the regulations, the board had the power to impose a discovery rule by adjudication and thereby hold that Burke's request was untimely. We conclude that the answer in both instances is no.
1. Whether the 1998 regulations, which did not explicitly contain a discovery rule, should be read as continuing the rule despite their silence
[14] When the board promulgated its regulations interpreting former AS 23.30.041(c), it codified its prior decisions about what constituted an unusual and exten-vating circumstance.53 Neither regulation mentions the discovery rule.54 The conflict between the previously-imposed discovery rule and the proposed regulation interpreting "unusual and extenuating cireumstances" was brought up in public comments about the regulation: A public commenter, a workers' compensation attorney, filed a comment noting that the proposed regulation was a departure from board case law imposing a discovery rule and raised the concern that the regulation would "leave open the amount of time an injured employee may request reemployment benefits."55 The board did not change the text of the regulation in response to the comment.56 From this there is at least a suggestion that the board declined to continue, by means of its rulemaking authority, the discovery rule it had previously adopted through adjudication. The board's consideration of the discovery rule at the time it promulgated the regulations further persuades us that the board must use rule-making rather than adjudication to effectuate the requirements that an employee must meet in order to request a reemployment eligibility evaluation under former AS 23.30.041(c).57
[867]*8672. Whether the board had the power, in the face of its decision to adopt new regulations that did not include a discovery rule, to impose a discovery rule by adjudication
[15] Burke asserts that the board cannot by adjudication "add requirements to the law that neither the legislature nor the executive branch in its rule-making power chose to add to the Act or regulations, respectively." We agree: If the board wished to add to the deadlines it explicitly set in the regulations-via adoption of a discovery rule-it was required to do so by regulation.58
We have previously held that an administrative agency can set and interpret policy using adjudication instead of rulemaking, absent statutory restrictions and due process limitations,59 and noted that the board has broad powers to administer the Alaska Workers' Compensation Act, including the authority to interpret statutes.60 But the board's power is not unlimited. Alaska law requires an agency to follow certain procedures, including public notice and an opportunity for public comment, before it can supplement or amend a regulation.61 Alaska Statute 44.62.640(2)(8) defines "regulation" to include "every rule, regulation, order, or standard of general application or the amendment, supplement, or revision of a rule, regulation, order, or standard adopted by a state agency to implement, interpret, or make specific the law enforced or administered by [the agency)." (Emphasis added.)
[16] Whether an agency action is a regulation is a question of law that does not involve agency expertise, so we apply our independent judgment.62 We have previously addressed the issue whether an agency action is an interpretation or an amendment of a regulation.63 In making this determination, we have looked at a variety of factors. We have compared the agency action with the statutory indicia of a regulation, including whether the action "implements, interprets or makes specific the law enforced or administered by the state agency" and "af-feets the public or is used by the agency in dealing with the public."64 Noting that many agency actions that are not regulations can affect the public, we have looked at the distinction drawn by the Court of Appeals for the District of Columbia between internal ageney practices, which do not require notice and comment rulemaking, and regulations, which do. That court identified the "critical feature" of an internal agency practice as "ageney actions that do not themselves alter the rights or interests of the parties, although [they] may alter the manner in which the parties present themselves or their viewpoints to the agency."65 Finally, we have [868]*868looked to see if the agency action provides new requirements or makes the existing requirements more specific.66
. Using these standards, we conclude that the board's discovery rule is a regulation that amends or supplements 8 AAC 45.510 and 45.520. The discovery rule, according to the board, implements, interprets, and makes more specific former AS 23.30.041(c),67 and it clearly affects the public-without the discovery rule, Burke's reemployment eligibility evaluation request would have been accepted. The discovery rule is also the type of agency action that alters the rights of the parties: It works to modify the requirements employees must meet in order to qualify for an eligibility evaluation under former AS 28.80.041(c). Finally, it changes the requirements for a reemployment eligibility evaluation request from those set out in the regulations: With the discovery rule, an employee who is requesting an evaluation more than ninety days after notice of injury may no longer satisfy the statutory requirements by submitting a written request to the Reemployment Benefit Administrator that is "complete in accor-danee with [8 AAC 45.510(b) ]."68
The dissent argues that it was reasonable for the board to interpret its regulation as creating a new ninety-day period to request reemployment benefits and that it would be unreasonable to interpret the regulation to allow an unlimited time to file a request onee an extenuating cireumstance ended.69 As to the first point, it is true that the board could have adopted a regulation to provide for a new ninety-day period, but it did not do so. This is critical, because there is no doubt that the interpretation given by the board here-enforcement of a discovery rule-'"interprets and makes more specific" the former statute and it does so in a way that alters the rights of the parties. In these cireumstances, an agency must act through rule-making, not adjudication.70 As to the dissent's second argument-that it would be unreasonable to interpret the regulation as allowing an unlimited time to file a request-the legislature in the former statute set no limit upon requests once unusual and extenuating circumstances were shown; rather, it gave broad discretion to the Reemployment Benefit Administrator to consider the cireumstances justifying a late application.71 Here, the delay was about three months, certainly not an unreasonable amount of time given the length of time-about sixteen months-that passed before it had become evident that Burke would not be able to return to his former occupation.
The dissent concludes that the board's determination that the new regulation contained a discovery rule was "readily predictable." But that conclusion ignores that the workers' compensation attorney commenting to the board 72 and the Reemployment Benefits Administrator73 both came to the opposite conclusion. And even if one had divined that the board might ignore the legal requirement that it act through rule-making, not adjudication, when it interprets and makes more specific a regulation in a way that alters the rights of a party, such prescience would not justify the board's action.
[17] Because the board chose to establish by regulation the procedure an applicant for a reemployment eligibility evaluation must use, it is bound by those regulations unless and until it repeals or amends the regulation using the proper procedure.74 Administra[869]*869tive agencies are bound by their regulations just as the public is bound by them.75 If the board wished to apply a discovery rule to requests that were made after the ninety-day period defined in the statute but which also met the statutory exeuse of unusual and extenuating cireumstances-as Burke's request did in this case-it was obligated to promulgate such a rule under Alaska law. We hold that the discovery rule imposed in this case is invalid because the board did not adopt it as a regulation under AS 44.62.010-.950. We therefore reverse the board's decision that reversed the Reemployment Benefit Administrator's determination finding Burke eligible for a reemployment eligibility evaluation.76
v. CONCLUSION
Because substantial evidence does not support the board's conclusion that Burke was not entitled to TTD benefits from March 19 to November 19, 2002, we REVERSE the board's decision denying him TTD benefits for that period of time. We also REVERSE the board's refusal to order reimbursement for Burke's travel to attend the hearing and its reversal of the Reemployment Benefit Administrator's decision. We AFFIRM the board's decision in all other respects.
BRYNER, Justice, not participating.