If an agreement on which the finance charge is computed in advance so provides, the holder of the agreement may collect a delinquency or collection charge of the lesser of $10 or 5 percent of the amount of any payment in default, if the default has continued for at least 10 days. In addition to the delinquency or collection charge, the agreement may provide for the payment of: Attorney’s fees not exceeding 15 percent of the amount due and payable under the agreement; and Court costs. Attorney’s fees may be collected only if the agreement is referred for collection to an attorney who is not a salaried employee of the holder.