12 Pa.C.S. § 6343: Late fees.

(a) Closed-end credit agreement.--

(1) A closed-end credit agreement may provide for the payment by the buyer of a late fee on each installment in default for a period of not less than ten days in an amount not in excess of 5% of the installment or $10, whichever is less.

(2) Only one late fee may be collected on an installment regardless of the period that it remains in default.

(b) Open-end credit agreement.--A late fee may be assessed on an open-end credit agreement regarding each minimum payment not paid in full on the payment due date of the statement on which the minimum payment first appears.