You can only deter smart people with punishments. Dumb people, on the other hand, don't realize the implications and consequences of their actions. From all that I have seen so far Jon definitely qualifies as a dumb guy .
So no, I don't want to deter anybody from cheating. I don't want to better the world or make other people think twice. I only want Jon to have a reality check. I don't care about wether his career ends or not, because he obviously doesn't care either.
Give him 6 years. It will take at least 2 years until he admits to himself that he did something wrong, the other 4 years will be his punishment.