Section 196.645 - Rate changes(1) The commission, upon complaint or upon its own motion, may proceed to investigate and determine whether a public utility's rates should be changed by reason of a change in the cost of an energy, commodity or service resulting from a change in charges for the energy, commodity or service if: (a) The rates of the public utility are based on the cost of the energy, commodity or service furnished to the public utility which the public utility furnishes or distributes to its consumers; and(b) The charges for the energy, commodity and service are regulated by an authority of the federal government and the federal authority has prescribed the change in charges.(2) The commission may make a change in rates under sub. (1) effective as of the effective date of the order of the federal authority prescribing the change in charges. (3) Notwithstanding ss. 196.60(3) and 196.604, the commission may determine and require payment by the public utility to its consumers of any sums which the public utility received from the consumers subsequent to the effective date of its order under this section and which are in excess of the rates prescribed by the commission under this section. This section does not authorize the use of an excessive earnings test to determine whether a refund received by a utility when its wholesaler's rate was lowered is to be distributed or retained. Algoma, Eagle River, New Holstein, Stratford, Sturgeon Bay & Two Rivers v. PSC, 91 Wis. 2d 252, 283 N.W.2d 261 (Ct. App. 1978).