Agreed. Also, what's the debate? 21 year sentence, then 5 years after that, then another 5, etc. This guy isn't getting out, or if he does, he will be a very old man. And I'm OK with that, because I believe the prison officials in Norway are capable of determining whether someone is rehabilitated or not, and I personally doubt that this man can ever be rehabilitated (to where we could be reasonably certain he wouldn't re-offend).
To me, the only fun debate is, could this system be implemented in a country like the US, where offenders are usually less educated and more violent than in Norway. AKA can a 'liberal' prison system fix a lifetime of economic disparity and under-education?