Delinquency and collection charges; court costs and attorney’s fees.

A home improvement contract may provide for the payment by the owner of a delinquency and collection charge on each installment in default for a period of not less than 10 days in an amount not in excess of 5 percent of such installment. However, only one such delinquency and collection charge may be collected on any installment, regardless of the period during which it remains in default. A contract may also provide for the payment of court costs actually incurred and of attorney’s fees not exceeding 20 percent of the amount due and payable under such contract, if it is referred to an attorney not a salaried employee of the seller or holder for collection.