Michigan Compiled Laws, Chapter 600. Revised Judicature Act of 1961 § 600.4921

Sec. 4921. (1) If a party has rejected an evaluation and the action proceeds to trial, that party shall pay the opposing party's actual costs unless the verdict is more favorable to the rejecting party than the mediation evaluation. However, if the opposing party has also rejected the evaluation, that party is entitled to costs only if the verdict is more favorable to that party than the mediation evaluation.

(2) For the purpose of subsection (1), a verdict shall be adjusted by adding to it assessable costs and interest on the amount of the verdict from the filing of the complaint to the date of the mediation evaluation. After this adjustment, the verdict is considered more favorable to a defendant if it is more than 10% below the evaluation, and is considered more favorable to the plaintiff if it is more than 10% above the evaluation.

(3) For the purpose of this section, actual costs include those costs taxable in any civil action and a reasonable attorney fee as determined by the trial judge for services necessitated by the rejection of the mediation evaluation.

(4) Costs shall not be awarded if the mediation award was not unanimous.