Norway will have built that authority into their system. Ironically, that adjustment is completely consistent with the aspirations of those Americans who oppose the parole system. The difference only being that Norway allows the decisions to be made by capable professionals instead of the victims' loved ones.
You've left yourself nothing to argue except the success and merits of their system Bob.
Under any sane, civilized society's system of justice, if one is convicted of a crime, and is sentenced to X years in prison, when he has served those X years in prison, he has completed his sentence,
“paid his debt to society”, and is released. Government doesn't get to decide, after the fact, that the convict was given too light a sentence, and impose additional punishments beyond what was originally sentenced, unless and until the convict commits additional crimes, and is convicted thereof.
Parole is a condition under which a convict may be released from prison before having completed his full sentence; not a way that he can be held beyond his sentence.
Of course, no sane, civilized society would ever sentence a mass murderer to only three months for each victim that he murdered. That would be an inexcusable betrayal of the general public, that the justice system has a duty to protect from such subhuman filth.
You seem to be trying to praise Norway for being
“humane” in never sentencing a criminal to more than twenty-one-years, no matter hos serious the crime, no matter how much of a threat the subhuman criminal piece of shit may pose to actual human beings; and then defending an apparent power on Norway's part, even to betray the convicted, by refusing to release them once the sentence has been fulfilled. This is seriously fucked-up, in two opposite directions at once.