Mich. Comp. Laws § 400.100
Persons who were employees of a city or county department of social welfare immediately prior to the effective date of this amendatory act, who (1) were members of a city or county retirement system and (2) become members of the state employees' retirement system, shall be entitled to benefits provided by Act No. 88 of the Public Acts of 1961, as amended, entitled "An act to provide for the preservation and continuity of retirement system service credits for public employees who transfer their employment between units of government", notwithstanding that the city or county might not have adopted the said Act No. 88. Whenever the service requirements for benefits to be paid under Act No. 240 of the Public Acts of 1943, as amended, to the said persons who become members of the state employees' retirement system are lower than the service requirements in the said Act No. 88, the provisions of the said Act No. 240 shall apply with respect to the said persons.
MCL 400.100