Goodbye, Yellow Brick Road - S6-E21
Plot hole: In the beginning of the episode, Joey and Audrey are talking in their dorm room. Audrey makes a comment that "Our time in this particular room is over". They have been in the same dorm room (27) for two years now, their Freshman and Sophomore years at Worthington. They still have 2 more years to go. What would make Audrey think that they would suddenly have to change dorm rooms when they've had the same room the entire time? Or that they wouldn't still be roommates the next academic year at Worthington? Audrey is staying to take Summer School classes so she doesn't have to leave the University. (00:08:40)
Answer: It's only explained once in the series. Jack says to Andie "I tried to start kindergarten without you", meaning Andie was smart enough to start school early.