Sec. 36a-778. (Formerly Sec. 42-91). Delinquency and collection charges. The holder of any retail installment contract or any installment loan contract shall not receive or collect any charges or expenses for delinquency and collection except as follows: The holder of a retail installment contract or installment loan contract, other than a contract for the purchase of a commercial vehicle, may collect a delinquency and collection charge for default in the payment of any such contract or installment thereof, when such default has continued for a period of ten days, such charge not to exceed five per cent of the amount of the installments in default or the sum of ten dollars, whichever is the lesser; provided this provision shall have no application to installment loan contracts regulated by sections 36a-555 to 36a-573, inclusive. The holder of any retail installment contract or any installment loan contract for the purchase of a commercial vehicle, as defined in section 36a-770, may collect a delinquency and collection charge for default in the payment of any such contract or installment thereof, when such default has continued for a period of ten days, such charge not to exceed five per cent of the amount of the installments in default, provided this provision shall have no application to installment loan contracts regulated by sections 36a-555 to 36a-573, inclusive. In addition to any such delinquency and collection charge, the retail installment contract or the installment loan contract may provide for the payment of attorney's fees not exceeding fifteen per cent of the amount due and payable under such contract when such contract is referred to an attorney, not a salaried employee of the holder of the contract, for collection, plus the court costs. The restriction on charges herein provided shall not apply to any expenses permitted under section 36a-785.