Mich. Comp. Laws § 500.3416

Sec. 3416. An insurer shall include in a disability insurance policy, other than a health insurance policy, a provision as follows: TIME OF PAYMENT OF CLAIMS: Indemnities payable under this policy for a loss other than loss for which this policy provides a periodic payment will be paid immediately upon receipt of due written proof of the loss. Subject to due written proof of loss, all accrued indemnities for loss for which this policy provides periodic payment will be paid ....................... (insert period for payment that must not be less frequently than monthly) and any balance remaining unpaid on the termination of liability will be paid immediately upon receipt of due written proof.