Mich. Comp. Laws § 32.49c

Sec. 49c. Evidence of the amount of retirement pay or pension provided by the laws of the United States for military disability or military service shall be required before any retired officer of this state, with more than 10 years of actual state duty, shall be paid under the provisions of section 49 or 49b of this act. The amount so evidenced shall be deducted when computing the sum to which the said officer shall be paid by this state: Provided, That this deduction does not operate to deprive any retired officer of a combined total of federal and state retirement pay equal to the provisions of said sections 49 and 49b.