(1) With respect to a consumer credit sale including an open-end consumer credit sale pursuant to a seller credit card, and any refinancings or consolidations of all such credit sales, the parties may contract for a delinquency charge on any installment not paid in full within ten days after its due date, as originally scheduled or as deferred, in an amount not exceeding five dollars, which is not more than five percent of the unpaid amount of the installment.

(2) Notwithstanding subsection (1) the seller may contract for and receive a minimum delinquency charge not to exceed forty percent of five dollars as adjusted pursuant to § 37-1-109. The seller may contract for such a minimum charge even though the charge exceeds five percent of the unpaid amount of the installment.

(3) A statement in the agreement between the creditor and the debtor to the effect that the creditor may charge the maximum delinquency charge (or late charge) authorized by law entitles the creditor to impose a delinquency charge in the dollar amount specified in subsections (1) and (2) as adjusted pursuant to § 37-1-109 at the time the delinquency charge is imposed, subject to the five percent of the unpaid amount of the installment limitation, if applicable.

(4) A delinquency charge under this section may be collected only once on an installment however long it remains in default. No delinquency charge may be collected with respect to a deferred installment unless the installment is not paid in full within ten days after its deferred due date. A delinquency charge may be collected at the time it accrues or at any time thereafter.

(5) A delinquency charge pursuant to this section must not be collected on a payment that is otherwise a full installment payment for the applicable period and is paid on its due date or within ten days after its due date if the only delinquency is attributable to a late fee or a delinquency charge assessed on an earlier installment. It is the intent of the legislature that, in construing this subsection the courts be guided by interpretations to 16 C.F.R. § 444.4 and 12 C.F.R. § 227.15, as amended from time to time, relating to late charges, given by the Federal Trade Commission, Federal Reserve Board, and the Federal Courts.