(a) Every utility company, and every municipality whose rates for utility service are subject to the jurisdiction of the commission (utility), shall notify the commission, in the manner described in this section, of all tax refunds, including refunds in the form of offsets against the utility's liability to the taxing authority issuing the refund; and including, in the case of municipalities, reductions in the amounts properly chargeable as payments in lieu of taxes. This Part shall be inapplicable to ordinary operating refunds that are not attributable to negotiation or to new legislation, adjudication or rulemaking (such as refunds for overpayment of estimated taxes, and carry-backs of net operating losses and investment tax credits). For purposes of this Part, a refund is deemed to occur when the earlier of the following events occurs, regardless of the possibility of subsequent audit or litigations:

1. (1) the refund is authorized by decision of a competent agency or court; or
2. (2) the utility receives it or uses it as an offset to liability.

(b) The utility shall notify the cormmission within 60 days after the refund occurs if the refund:

1. (1) exceeds $1,500,000; or
2. (2) exceeds $1,000 and exceeds 0.2 percent of the utility's operating revenues for the most recent calendar year that ends more than four months before the refund occurs.

(c) In determining whether a refund exceeds 0.2 percent of operating revenues for purposes of paragraph (b)(2) of this section:

1. (1) in the case of a gas, electric, steam or combination utility, operating revenues shall be reduced by the amounts properly chargeable to the functional group of production operation and maintenance expense accounts;
2. (2) in the case of a combination utility, the refund shall be deemed to exceed 0.2 percent of operating revenues if, after the refund is allocated among the gas, electric and steam departments in a manner reflecting insofar as possible the extent to which the refund is related to each department's activities, one or more of the portions thus allocated exceeds 0.2 percent of the operating revenues of the department to which it is allocated;
3. (3) in the case of a water utility, operating revenues shall be reduced by the amounts properly chargeable to the functional groups of source of supply, and pumping operation and maintenance, expense accounts; and
4. (4) in the case of a telephone utility, operating revenues shall not include interstate revenues.