Mich. Comp. Laws § 38.1640a

Sec. 40a. (1) Effective October 1, 1996, after the retirant's or retirement allowance beneficiary's retirement allowance is increased under section 39a or 40, as applicable, a retirant or a retirement allowance beneficiary is entitled to have his or her retirement allowance increased as provided in this section. The retirement allowance of a retirant or retirement allowance beneficiary shall be increased each October 1, beginning with the later of October 1, 1995 or the first October 1 that is at least 12 months after the retirement allowance effective date. (2) The amount of the annual increase under this section shall be 2% of the retirement allowance that would be payable without application of this section. The annual increase under this section shall not exceed $500.00.