I don't quite agree with that assessment, though I never did understand why he wanted to re-do high school.
Young clone Jack asked Orig Jack that question, "Didn't you ever want to go back and do it all over knowing what you know now?"
Orig Jack says, "No".
To me this is perhaps the first indication that clone Jack is beginning to think as a unique person with new thoughts vs during the episode he had continued to behave as Orig Jack.
Clone Jack now realizes he needs to find a way to stand apart and by doing high school, even with the advantage he has, he'll redefine himself as a unique individual.
That was what I took from the exchange in the truck at episode end.
It was a bit too convenient that a group of girls instantly started taking to him, but whatever.