(1) Charges under section 8-820 shall be computed by application of the rate charged to the outstanding principal balance for the number of days actually elapsed without adding any additional charges, except that at the time the loan is made charges may be computed as a percentage per month of unpaid principal balances for the number of days elapsed on the assumption that the unpaid principal balance will be reduced, as provided in the loan contract, and such charges may be included in the scheduled installments. In the case of loans initiated by credit card or other type of transaction card, charges may be computed in any other manner agreed to by the parties and may include compounding of fees and charges.

(2) If a loan is prepaid in full by cash, a new loan, or otherwise after the first installment due date, the borrower shall receive a rebate of an amount which shall be not less than the amount obtained by applying to the unpaid principal balances as originally scheduled or, if deferred, as deferred, for the period following prepayment, according to the actuarial method, the annual percentage rate previously stated to the borrower pursuant to the federal Consumer Credit Protection Act. The licensee may round the annual percentage rate to the nearest one-half of one percent if such procedure is not consistently used to obtain a greater yield than would otherwise be permitted. Any default and deferment charges which are due and unpaid may be deducted from any rebate. No rebate shall be required for any partial prepayment. No rebate of less than one dollar need be made. Acceleration of the maturity of the contract shall not in itself require a rebate. If judgment is obtained before the final installment date the contract balance shall be reduced by the rebate which would be required for prepayment in full as of the date judgment is obtained.

(3) The charges retained by the bank may be increased to the extent that delinquency charges are computed on earned charges in accordance with the next succeeding sentence. Delinquency charges on any scheduled installment or portion thereof, if contracted for, may be taken, or in lieu thereof, interest after maturity on each such installment not exceeding the highest permissible interest rate.