A customer may change his electric supplier, as defined in § 16-1, at any time. The electric distribution company, as defined in said § 16-1, and electric supplier may each charge a reasonable fee, as approved by the Public Utilities Regulatory Authority, to make a change in the customer’s supplier to reflect the actual cost to read the customer’s meter and make changes in its billing records, except that every customer may seek a change in his electric supplier without charge once in any twelve-month period if the change occurs at the end of the customer’s regularly scheduled meter reading and billing cycle.