Mich. Comp. Laws § 421.65

Sec. 65. (1) If this 1971 amendatory act is given immediate effect, the effective date of paragraph (1a) of subsection (b) of section 27 and paragraph (4) of subsection (g) of section 27 shall be the first day of the calendar week containing the thirtieth day after it is approved by the governor or becomes law without his approval. (2) An individual who has a current and unexhausted benefit year on the effective date as provided in subsection (1) shall have his weekly benefit rate and the maximum amount of benefits recomputed in accordance with this amendatory act with respect to any week of unemployment beginning on or after that date on that portion of his benefit rights not exhausted prior to that date but his weekly benefit rate and maximum amount of benefits established and not exhausted prior to the aforementioned effective date shall not be subject to reduction or elimination by such recomputation. (3) Except as provided in subsections (1) and (2), this 1971 amendatory act shall become effective January 1, 1972.