A retail installment contract may provide for payment by the buyer of a delinquency charge on each installment in default for a period not less than 10 days. Such charge may not exceed 5 percent of such installment. A retail installment contract or a revolving account may provide for the payment of reasonable attorney's fees if referred for collection to an attorney not a salaried employee of the retail seller and for the payment of court costs.
Fla. Stat. § 520.37