Mich. Comp. Laws § 440.9709: Priority.

Sec. 9709.

This amendatory act determines the priority of conflicting claims to collateral. However, if the relative priorities of the claims were established before this amendatory act takes effect, this article as in effect before this amendatory act takes effect determines priority.

For purposes of section 9322(1), the priority of a security interest that becomes enforceable under section 9203 of this amendatory act dates from the time this amendatory act takes effect if the security interest is perfected under this amendatory act by the filing of a financing statement before this amendatory act takes effect which would not have been effective to perfect the security interest under this article as in effect before this amendatory act takes effect. This subsection does not apply to conflicting security interests each of which is perfected by the filing of a financing statement described in this subsection.