Mich. Comp. Laws § 418.613

Sec. 613. If the agency determines that services are covered employment under section 161(1)(n) and the agency received the request on or after the effective date of the amendatory act that added this subsection and before January 1, 2013, the employer shall not be subject to penalties or interest on underpayments or other violations before the date of the determination arising from the misclassification of those services.