Upon the recommendation of the Department of Corrections, the Parole Commission shall have the authority to determine the exact period of imprisonment to be served by defendants sentenced under the provisions of s. 921.18, but a prisoner shall not be held in custody longer than the maximum sentence provided for the offense.

s. 6, ch. 57-366; s. 18, ch. 61-530; s. 129, ch. 70-339;