(a) In any criminal action in which the defendant is convicted, the judge, if the judge sentences the defendant to confinement, shall direct that for the purpose of computing defendant’s sentence and parole eligibility and conditional release dates thereunder, that such sentence is to be computed from a date, to be specifically designated by the court in the sentencing order of the journal entry of judgment. Such date shall be established to reflect and shall be computed as an allowance for the time which the defendant has spent incarcerated pending the disposition of the defendant’s case. In recording the commencing date of such sentence the date as specifically set forth by the court shall be used as the date of sentence and all good time allowances as are authorized by the secretary of corrections are to be allowed on such sentence from such date as though the defendant were actually incarcerated in any of the institutions of the state correctional system.

(b) In any criminal action in which probation, assignment to a conservation camp or assignment to community corrections is revoked and the defendant is sentenced to confinement, for the purpose of computing the defendant’s sentence and parole eligibility and conditional release date, the defendant’s sentence is to be computed from a date, hereafter to be specifically designated in the sentencing order of the journal entry of judgment. Such date shall be established to reflect and shall be computed as an allowance for the time which the defendant has spent in a residential facility while on probation, assignment to a conservation camp or assignment to community correctional residential services program. The commencing date of such sentence shall be used as the date of sentence and all good time allowances as are authorized by law are to be allowed on such sentence from such date as though the defendant were actually incarcerated in a correctional institution.

(c) Such credit is not to be considered to reduce the minimum or maximum terms of confinement authorized by law for the offense of which the defendant has been convicted.