My daughter was on the borderline between L3 and L4 and that year they decided to push her and her teammates to L4 even though they were a little behind. The advantage was that she continued to progress and she was much happier working the harder routines and being challenged. The downside is that she had a pretty weak year in terms of podium placement because she was a bit behind from the start and in L4 and L5 you get a lot of girls repeating and so the kids are competing against girls in their second year of a level. Because of the weak L4 season, she repeated L4 and she had a much stronger year. Her bars improved tremendously and by the time she was ready to go to L5, she was much more ready to work the tougher skills. Ideally, the kids should uptrain while they are in a level so that they can be more ready to move when the time comes. Looking back, she would have been very frustrated repeating L3 because she was ready to do more. The year she repeated L4, she wanted to repeat. She was not ready at all to progress to L5 that year.