Rule 21. Upon a residential customers request, a utility shall bill a residential customer with a satisfactory payment history under an equal monthly billing program, if the commission finds that the billing program assures reasonable billing accuracy. If a residential customer has a credit balance of more than $10.00 at the end of the program year, upon the request of the customer, the utility shall either return the credit balance or credit it to the next month's bill. If the balance is less than $10.00, the utility shall credit the amount to the residential customer's account.
Mich. Admin. Code R. 460.121