As Krieger explains, “the rule against retroactive ratemaking encourages efficiency because the utility will endeavor to increase profits under the approved rate. If the utility knows that it can recoup past losses retroactiv[ely] or that ratepayers can obtain refunds of excess profits, it will have little or no incentive to operate efficiently.” 175 Mich.App. 584, 438 N.W.2d 616 (1988). FN63.
The PSC is given broad discretionary power to set rates. See General Motors Corp v PSC No 2, 175 Mich App 584, 588; 438 NW2d 616 (1988). It would seem unnecessary, and somewhat unproductive, for the Legislature to try to anticipate and list all of the contingencies that could have a bearing on determining a proper GCR factor.
Arguments without supporting citation are considered abandoned on appeal. General Motors Corp v Public Service Comm No 2, 175 Mich. App. 584, 590; 438 N.W.2d 616 (1988). In addition, we decline to address the new issues raised in plaintiff's reply brief because they are not properly before us. MCR 7.212(F).
The reviewing court must give due deference to the PSC'S administrative expertise and is not to substitute its judgment for that of the commission. General Motors Corp v Public Service Comm No 2, 175 Mich. App. 584, 589; 438 N.W.2d 616 (1988). I
MCL 460.6, 460.557; MSA 22.13(6), 22.157. As a reviewing Court, we must give due deference to the PSC'S administrative expertise and we will not substitute our judgment for that of the PSC. General Motors Corp v Public Service Comm No 2, 175 Mich. App. 584, 589-590; 438 N.W.2d 616 (1988). Consequently, we refuse to substitute our judgment with respect to the adoption of 1986 as the test year.
As Krieger explains, "the rule against retroactive ratemaking encourages efficiency because the utility will endeavor to increase profits under the approved rate. If the utility knows that it can recoup past losses retroactiv[ely] or that ratepayers can obtain refunds of excess profits, it will have little or no incentive to operate efficiently." 438 N.W.2d 616 (Mich. App. 1988). Id. at 587.