Mich. Comp. Laws § 780.830a

Sec. 80a. (1) If a defendant who has been sentenced to jail is ordered to pay restitution under section 76, and if the defendant receives more than $50.00 in a month, the sheriff may deduct 50% of the amount over $50.00 received by the defendant for payment of the restitution, and 5% of the amount over $50.00 received by the defendant to be retained by the sheriff as an administrative fee. The sheriff shall promptly send the money deducted for restitution to the court or to the crime victim as provided in the order of restitution when it accumulates to an amount that exceeds $100.00, or when the defendant is released to probation or discharged on the maximum sentence. (2) The sheriff shall notify the defendant and the court in writing of all deductions and payments made under this section. The requirements of this section remain in effect until all of the restitution has been paid. The sheriff shall not enter into any agreement with a defendant that modifies the requirements of this section. An agreement in violation of this subsection is void.