(a) General rule.--Pursuant to this section and the provisions of a closed-end credit agreement or an open-end credit agreement, a seller and holder may charge, receive and collect a finance charge.
(b) Closed-end credit agreement.--A finance charge under a closed-end credit agreement shall be:
(1) measured for a period between the date of the agreement and the due date of the last installment; and
(2) calculated for the period according to the actuarial method or the United States Rule method, at a rate agreed to by the buyer and the seller or holder.
(c) Open-end credit agreement.--
(1) Except as provided in paragraph (2), a finance charge on an open-end credit agreement:
(i) shall be computed based on the outstanding monthly balances; and
(ii) may not exceed the rate agreed to by the buyer and the seller or holder.
(2) A minimum finance charge of $1 per month may be made for each month, if the finance charge so computed is less than that amount.