Mich. Comp. Laws § 791.225

Sec. 25. Where the courts of more than 1 county are served by the same probation officer or officers, the compensation of such officer or officers and the expenses of administering probation service within such counties shall be met jointly by the boards of supervisors therein: Provided, That when it shall appear to the commission that any county is unable to adequately maintain its probation program according to the standards set by the state bureau of probation, then service grants to such an extent and under such conditions as the commission may determine, may be made available to said county: Provided, That uniform rules to be followed in making available such service grants first shall be promulgated by the commission.