The issue came up after the Iowa Supreme Court ruled that mandatory minimum sentences automatically imposed for those who committed crimes as juveniles constituted cruel and unusual punishment under the Iowa Constitution.
Prisoners convicted of crimes with mandatory minimums receive time off their sentences for good behavior at a rate slower than those who don’t have the mandatory sentences. A district court ruled that the slower rate of time off for good behavior should stay in place for some crimes, even after the resentencing without a mandatory minimum sentence.
The Court of Appeals disagreed, as did the Iowa Supreme Court, which says the mandatory minimum and slower accumulation rate are inextricably linked, and there cannot be a slower rate for good behavior time without the a mandatory minimum sentence.
See the ruling here: mandatory-miminum-ruling-pdf