Amount of Deposit. The deposit required by the utility may not be less than $5 or more in amount than 2/12 of the estimated charges for service for the ensuing 12 months, except that an amount equal to 3/12 of the estimated charge for service for the ensuing 12 months will be permitted for those utilities which bill quarterly. If the actual billing is substantially different from the estimated charge for service, then the amount of the deposit may be adjusted to the applicable proportion of the actual billing. Deposit Receipt. Each utility shall issue a receipt of deposit to each customer from whom a deposit is received, and shall provide means by which a depositor may establish his claim if his receipt is lost. Interest on Deposits. Each utility shall pay simple per annum interest on a deposit from the date of receipt by the utility. The rate in §C(1) of this regulation shall be a weighted monthly average of calendar year rates appropriate to the holding period. Calendar Year Rates. The calendar year rates shall be established in December of each year to be effective January 1 of the following year. The rate shall be equal to the average of the percent yields of 1-year treasury constant maturities for September, October, and November of the preceding year. Payment of Interest. Interest shall be paid annually, if requested by the customer, or at the time the deposit is returned. Cessation of Interest. The obligation to pay interest on a deposit shall cease upon one of the following events: The date it is returned or credited to the customer's bill for service; The date service is terminated; or The date notice is sent to the customer's last known address that the deposit is no longer required. Record of Deposit. Each utility shall keep records to show: The name and address of each depositor; The amount and date of the deposit; and Each transaction concerning the deposit. Unclaimed Deposits. Unclaimed deposits, with accrued interest, shall be credited to an appropriate account, or shall otherwise be disposed of in accordance with Commercial Law Article, Title 17, Annotated Code of Maryland. Payment of Deposit. A utility shall provide an installment plan for the payment of deposits in excess of $50. The installment plan may require a customer to pay the greater of $50 or one-third of the total deposit by the date that service is provided. A utility shall offer a customer the option to pay a required deposit amount: Between $50 and $150 in even installments over a period of at least 8 weeks; or Over $150 in even installments over a period of at least 12 weeks. The customer shall be notified of this right at the time of the initial deposit request and in the utility's customer rights pamphlet.