Mich. Comp. Laws § 15.565

Sec. 5. (1) If a collective bargaining agreement or other contract that is inconsistent with sections 3 and 4 is in effect for 1 or more employees of a public employer on September 27, 2011, the requirements of section 3 or 4 do not apply to an employee covered by that contract until the contract expires. A public employer's expenditures for medical benefit plans under a collective bargaining agreement or other contract described in this subsection shall be excluded from calculation of the public employer's maximum payment under section 4. The requirements of sections 3 and 4 apply to any extension or renewal of the contract. (2) A collective bargaining agreement or other contract that is executed on or after September 27, 2011 shall not include terms that are inconsistent with the requirements of sections 3 and 4.