407.756.  Law, applicability to existing and future contracts. — The provisions of sections 407.750 to 407.756 shall apply to all continuing or nonrenewable contracts and all other contracts entered into, amended, or renewed after August 28, 1991.  Any contract in force and effect on August 28, 1991, which, by its terms, will terminate on a date subsequent thereto, is governed by the law as it existed before August 28, 1991.