Clarifying the circumstances under which parties to a contract may agree to the payment of late fees; authorizing the parties to a contract to agree to require that late fees be paid when a party fails to make a payment when due; requiring full disclosure of any late fees; limiting the amount of late fees in a consumer contract; prohibiting the imposition of late fees in a consumer contract earlier than 20 days after the payment due date; defining "late fee"; and providing for the application and interpretation of the Act.