Michigan Compiled Laws, Chapter 700. Estates and Protected Individuals Code § 700.1213

Sec. 1213. If an individual includes a provision in a will, trust document, or beneficiary designation that is designed to reduce federal estate tax liability to zero or the lowest possible amount payable by describing a portion or amount measured by reference to the unified credit, the exemption equivalent, other credits, or other deductions, then unless specifically stated otherwise, the reference to the credits, exemption, or deductions shall be considered to include a reference to the family-owned business deduction available under section 2057 of the internal revenue code of 1986, 26 USC 2057, if that deduction is elected. Unless specifically stated otherwise, and subject to section 2723, 1 the reference to the unified credit or exemption equivalent, or to the family-owned business deduction, shall be considered to refer to the credit, exemption, or deduction as it exists at the time of death of the individual.