If by LONG you mean just as long as the crime itself takes to be in lapse, as in forever for murder... then yes, I'll agree on the LONG part. However, if someone agreed to go to jail and to work off his punishment instead of losing a large chunk of lifespan and then tries to escape, I dont agree on then suffering only the same spiritloss as if he was executed at the first time. It should be more than that, if he gets caught again, because being a liar about his motives came on top of the crimes. Otherwise, no one is going to get executed, because everyone will go to jail and try to escape. Escaping prison should be possible, if the guards do several mistakes, but certainly not easy or the norm. And it should come with a risk. Losing the same amount of lifetime that one would have lost anyway is not really a risk that would stop anyone.
However, I'm clearly a fan of working off the crimes in a productive way that pays back what was done and some on top with no spiritloss as a reward for doing so (but then higher spiritloss if the deviant flees and has to be catched again).