Moreover, Commission decisions are entitled to great weight as being the judgment of a tribunal appointed by law and informed by experience. ( Village of Apple River v. Illinois Commerce Comm'n (1960), 18 Ill.2d 518, 523, 165 N.E.2d 329, 332; United Cities Gas Co. v. Illinois Commerce Comm'n (1992), 225 Ill. App.3d 771, 777, 587 N.E.2d 581, 585.) In reviewing Commission decisions, the court is limited to determining whether (1) the Commission's decision was within the scope of its statutory authority, (2) the Commission made findings adequate to support its decision, (3) the findings have substantial evidentiary support in the record, and (4) the Commission's decision infringed upon constitutional rights.
1. Case Law In United Cities Gas Co. v. Illinois Commerce Comm'n (1992), 225 Ill. App.3d 771, 587 N.E.2d 581, this court ruled that a consulting and noncompetition agreement conferred a benefit to United Cities' ratepayers. Accordingly, we reversed the decision of the Commission and decided that the costs associated with that agreement were "a legitimately incurred cost of service which it [(United Cities)] is entitled to recover in its rates."
As noted by the appellate court below, the Commission is not prohibited from changing its policies provided that such change is not done in an arbitrary or capricious manner. See 225 Ill. App.3d 771. Moreover, notwithstanding references in the order to a change in allocation methodology from what was adopted in the Barnsley Order, the order does not in substance change the method used by United Cities in allocating its total demand charges.
Central Illinois Public Service Co. v. ICC, 268 Ill. App.3d at 479. See also United Cities Gas Co. v. Illinois Commerce Comm'n, 225 Ill. App.3d 771, 782, 589 N.E.2d 581 (1992) (Commission may not depart from prior practices and customs in interpreting its procedural rules, especially where there may have been detrimental reliance on such prior agency interpretations). The Commission's decision here is not based on a new and different interpretation of a prior rule but, rather, is based on the Commission's long-standing policy of deterring transportation customers from taking unauthorized gas through the imposition of an appropriate charge.
• 2 In reviewing an ICC decision, this court is limited to determining whether (1) the ICC decision was within the scope of its statutory authority, (2) the ICC made findings adequate to support its decision, and (3) the decision infringed upon constitutional rights. ( United Cities Gas Co. v. Illinois Commerce Comm'n (1992), 225 Ill. App.3d 771, 777, 587 N.E.2d 581, 585.) An order of the ICC will not be set aside unless it is against the manifest weight of the evidence.