CONCURRING AND DISSENTING OPINION OF
ABE, J.I concur with the substance of the opinion of my brother Kobayashi, and therefore also believe that the decisions and orders appealed from must be set aside. However, I find an additional important reason for setting aside the decisions and orders, not discussed by the opinion of my brother Kobayashi. Also, I feel that the terms of the order in the plurality opinion, with which order I concur only reluctantly, amount to an unwise exercise of our judicial power. Therefore, because of these substantial differences with the opinions of the other members of this court, and because of the extreme importance of the matters here at issue, I deem it necessary to set forth my views separately.
I.
Even assuming arguendo that my brother Marumoto *671is correct in his opinion that the findings of fact made by the P.U.C. are precise enough so as not to be insufficient as a matter of law under HRS § 91-12, nonetheless, those findings are deficient in another significant way. Leaving aside the problem of whether the findings of fact are sufficiently precise, the rates set are invalid because of the appellee’s conspicuous failure to introduce adequate evidence on, and the P.U.C.’s egregious laxity in its study of, the crucial “separations” procedure. I would hold that the decisions and orders appealed from must be set aside because they are unsupported by reliable, probative, and substantial evidence, as required by the Hawaii Administrative Procedure Act, HRS § 91-10(1).
In our federal system, the FCC has statutory authority to regulate rates for interstate and international telephone service, while the Hawaii P.U.C. determines intrastate charges. A “separations” procedure, or formula, determines the respective jurisdictional areas of each of these agencies, by apportioning between intrastate operation and all other operations the total telephone property, revenues, expenses, taxes, and reserves. Cf. Smith v. Illinois Bell Tel. Co., 282 U.S. 133 (1930).
Appellee admits the obvious: this is a highly confusing and technical area. This court ordinarily defers to administrative expertise in such areas. Re App’n of Hawaiian Elec. Co., 42 Haw. 233, 238, 245 (1957). I would normally be inclined to follow the rule of deferring to agency expertise in devising an appropriate “separations” procedure, but I can find no signs that the “separations” procedure settled upon was based on an exercise of even independent judgment, much less expertise. While I defer to agency expertise, I do not defer to what is clearly an arbitrary decision, without adequate support in the record.
In decision and order no. 2853 the Commission “found” that appellee’s
. . . use of the jurisdictional separations procedure *672specified in the FCC 1969 Report and Order in Docket No. 17975 and in the NARUC-FCC 1969 Separations Manual for purposes of the proceeding (which is based on the test year 1970) is proper and reasonable.
The issue raised before the P.U.C. and on this appeal is the applicability of the formula in the above FCC Report (which formula was devised for the contiguous forty-eight states) to the unique conditions raised by the geographical location of the Hawaiian Islands.1
The appellee sought the rate increase here challenged on the basis of allegedly deficient profits on intrastate operations. “Separation” of investment in plant and equipment used jointly by intra- and interstate and foreign-operations, and “separation” of expenses (commonly incurred in all operations) into the intra- and interstate and foreign-components thereof is obviously a threshold issue in the determination of the merits of appellee’s request for intrastate rate increase. The appellee carries the burden of proof in its application for a rate increase, Ringsby Truck Lines, Inc. v. United States, 263 F. Supp. 552, 554 (D. Colo. 1967), appeal dismissed, sub nom. National Small Shipments Traffic Conf. Inc. et. al v. Ringsby Truck Lines Inc. et. al., 389 U.S. 576 (1968); New Jersey Suburban Water Co., v. Bd. of Public Utility Commissioners, 122 N.J.L. 54, 4 A.2d 47, 48 (1939), aff’d, 123 N.J.L. 303, 8 A.2d 350, cert. den. sub nom. McGregor, Receiver v. Bd. of Public Utility Commissioners, et. al., 309 U.S. 663 (1940). It follows a fortiori that the appellee has the burden of developing a proper “separations” formula.
It is clear to me that this burden was not carried, and it was therefore reversible error for the P.U.C. to order *673any rate increase, for theré is no reliable, probative and substantial evidence in the record to support that increase.
Although the separations formula of the FCC Report was adopted by the P.U.C., at no point in the proceedings were the merits of this formula even discussed. The appellee introduced evidence at the hearings that representatives of appellee, of the FCC, and of the staff of the P.U.C. agreed at an earlier meeting that the FCC Report’s formula was “generally reasonable” as applied to Hawaii. This assertion was controverted by the case presented by the P.U.C. staff. Both parties introduced conflicting second hand evidence as to the past and then current opinions of the FCC experts who had attended the meeting. The only other evidence on the appropriateness of the separations formula used in computation is a restatement and highlighting of assertions in the FCC Manual. Even the sum total of all this evidence is not the reliable, probative and substantial evidence that must be the basis of any agency order.
Furthermore, at no point in the record is there an indication of the commission’s effort to deal with the substance or merits of the conflicting claims. Appellee itself as much as admits that the P.U.C. was derelict in this duty. Since the FCC accepts the validity of its own Report’s formula, appellee states “there is no reason why the Hawaii Commission should embark on the formidable task of designing a formula peculiar to Hawaii.”2 *674On the contrary, there is every reason why the P.U.C. must do so, including the requirements of HRS § 91-10(1).
II.
I cannot fully agree with the plurality opinion that invalid decisions and orders that establish invalid rates should continue to have any legal effect whatsoever, even temporary effectiveness while the P.U.C. has an opportunity to make necessary findings of fact and conclusions of law in accordance with our opinion to remand.
Any analysis of appropriateness of remedies must begin with the authority given this court by HRS § 91-14(g). This statutory provision grants the court a wide discretion because the court may
affirm the decision of the agency or remand the case with instructions for further proceedings; or it may reverse or modify the decision and order if the substantial rights of the petitioners may have been prejudiced ....
This statute empowers this court to grant relief, inter alia, in the form ordered in the plurality opinion, or in the form of a remand and an order requiring appellee to refund the difference between the rates in effect prior to the decisions and orders that are annulled and those established by those invalid decisions and orders. I believe that this latter form of relief, in the form of a remand and a refund, should have been ordered. Therefore, I concur only reluctantly with the order in the plurality opinion, and do so only in order to prevent this court from being split in an unacceptable way.
The dissenting opinion of my brother Marumoto states that a refund would be improper because no stay was sought under HRS § 269-16, prior to the appeal taken in this case. The relevant portion of the statute apparently relied upon is:
*675The appeal shall not of itself stay the operation of the order appealed from, but the supreme court may stay the order after a hearing upon a motion therefor ....
I would not disagree with the proposition that this statute required that appellant seek a stay from this court if appellant desired to prevent the appellee from collecting the higher rates provided for in the decisions and orders challenged here, if appellant wished to achieve this result prior to our disposition of this case in this appeal. But HRS § 269-16 is not dispositive as to the power of this court to order a refund at this stage in the proceedings.
In construing other rules on stay of proceedings resembling the applicable rules in the statute, it has been held that a failure to seek a stay does not deprive a litigant of his right to an effective appeal, providing that there is no resultant and substantial prejudice to appellee and providing that the appellant makes clear his intention to appeal. This general rule has been applied even where, because of partial or complete execution of a judgment, a reversal on appeal would present serious practical problems in restoring the parties to their former positions. Hawaiian Paradise Park Corp. v. Friendly Broadcasting Co., 414 F.2d 750, 752 (9th Cir. 1969).
To suddenly adopt a rule foreclosing the issue of the right to refund because of a mere tactical decision on the part of appellant would effectively penalize that party for its failure to take what is an optional, not a mandatory, step. The potentially heavy financial burdens imposable under HRS § 269-16 may very well have deterred appellant from seeking a stay. But since moving for a stay is not mandatory, it is not necessary to justify or excuse the failure of appellants to seek that relief. Furthermore, the record shows adequate notice of appeal; and, there can be no prejudice to appellee by appellant’s failure to seek a stay, because appellant’s failure to act has left *676appellee in a better position than it could possibly have been in had appellant sought the stay.
Courts have split over the propriety of judicially ordered refunds following a declaration of invalidity, of the relevant decisions and orders setting utility charge rates. See, e.g., Village of North Palm Beach v. Mason, 188 So.2d 778, 780-1 (Fla. 1966); contra, City of Los Angeles v. California P.U.C., 7 Cal. 3d 331, 102 Cal. Rptr. 313, 497 P.2d 785, 802-06 (1972). To me, neither indulging in abstruse and recondite arguments as to which line of authority should be adopted, nor abstractly analyzing whether the annulled decisions and orders are, or should be, void or voidable, is likely to be fruitful. Rather, purely practical considerations suggest that judicially ordered refunds are most appropriate once we have determined that the decisions and orders are invalid.
Assuming that we might hold that the decisions and orders are invalid, appellee would have us leave current rates unchanged and remand to the P.U.C. for appropriate action, possibly including, inter alia, a P.U.C.ordered refund. The plurality’s decision apparently follows this line of reasoning as to any overcharges for the period between the date of the annulled decisions and orders and 30 days following our decision in this appeal. Thereafter, although the appellee may be able to collect the rate set by the invalid orders, the old rate is reinstated. The reinstatement of the old rate may necessitate a further adjustment in any rate set by the commission on remand, in order to compensate for any possible undercharges during this future period. To me, this approach renders the future task of the commission unjustifiably complex and certainly invites further and needless litigation.
But even if appellee’s. simpler suggestion were adopted, i.e., that the current rates continue until modification by the commission, further needless litigation is still to be anticipated. Appellee’s approach, adopted in *677part by the majority for the period that is prior to BO days following this opinion but subsequent to the promulgation of the decisions and orders appealed from, suggests a problem, because HRS § 269-16 may be interpreted as prohibiting retroactive action on the part of the commission. And, although Ch. 91 of HRS suggests that an agency may “repeal” a rule, the “repeal” concept is usually understood as including only prospective action. Since neither of these matters is before the court, I express no opinion on the extent of the P.U.C.’s retroactive powers, except to note that, at least arguably, the commission might be without any authority to carry out our mandate if refunds should be found to be appropriate under that mandate.
On the other hand, this court clearly has power to order a refund, for courts can act retroactively, and HRS § 91-14(g) gives this court what no statute gives the P.U.C., i.e., express authority to “reverse” an agency decision. Cf. City of Los Angeles v. California P.U.C., supra. Therefore, this court should order a refund of the monies collected under the invalid decisions and orders, and let the P.U.C. use prospective action to correct any inequity thereby resulting to the appellee. Such an approach is less difficult for the commission and will lead to a quicker promulgation of legal rates. It is also less likely to raise legal issues that, because they must be decided on appeal, will perforce delay still further the setting of fair telephone charge rates in Hawaii.
In the 1971 revision of the manual, which appellee agrees is substantially the same as the 1969 version, the statement appears: '‘(These procedures are not necessarily designed to apply to Alaska and Hawaii in view of the substantially different conditions existing in the case of these states).” Revised Separations Manual (Feb. 1971), p. 8 (emphasis added).
It should be noted that the appellee contends that ‘‘[i]t is hardly reasonable to expect the Hawaii Commission on its own and without help from anyone to develop its own separations formula, particularly when the country’s two leading experts on the subject (Messrs. Baker and Strassburg) have declared it unnecessary.” Thus it seems that the appellee forgets that it was its burden to show the reasonableness of the separations formula. The appellee continues to carry the burden, even if, as appellee contends, Hawaii users of interstate telephone services have been discriminated against because the NARUC-FCC formula results in an abnormally large apportionment of revenues, expenses, etc. being made to interstate services, when compared with the apportionment made as to the interstate services used by customers in the contiguous forty-eight states.