|(a) Meter unit indication. Each meter display shall indicate clearly the kilowatt-hours or other units of service for which a charge is made to the utilities' customer. (b) Reading of standard meters. As a matter of general practice, service meters shall be read at monthly intervals, and as nearly as possible on the corresponding day of each meter reading period, but may be read at other than monthly intervals if the circumstances warrant. The electric utility shall notify the customer of any changes to the customer's meter reading cycle. This subsection does not apply to advanced metering systems. (c) Reading of advanced meters. Advanced meters shall be read by the electric utility at intervals required by the Applicable Legal Authorities defined in §25.214(d)(1) of this title (relating to Tariff for Retail Delivery Service). (d) Customer-read program. For meters other than advanced meters, an electric utility in an area where retail competition has not been introduced, may use a customer-read program in which customers read their own meters and report their usage monthly. Such readings shall be considered an actual meter reading by the electric utility for billing purposes. However, an electric utility shall read the meters of customers on a customer-read program at least every six months to verify the accuracy of the electric utility's records.