Mich. Comp. Laws § 38.1205: Annual longevity payments.

Sec. 5.

A nonclassified employee shall be eligible for annual longevity payments on the same basis as classified employees, except that eligibility for longevity payment shall be determined by combining the years of service in both the classified and nonclassified service and the amount of payment determined by the equivalent longevity pay rates established by the civil service commission for nonclassified employees.