That makes sense. Have a final 5th season with 13 episodes to do the spring semester.
Actually, I would prefer they start fresh at the beginning of season 5, and pretend like we just didn't see the adventures of spring semester. Kick off season 5 as a return from an extended hiatus as "six months later". Would be able to give a more convincing reason for Jeff to be hanging around, probably (maybe the law thing wasn't working out the second time around).