Well, it depends on what type of gym you are at. If you are held back for no BHS on beam after you have very successfully completed the previous level, and have all other skills, you had better be at a gym that does tons of uptraining, and allows you to continue to train for the next level. If not, you're wasting a year. Some gyms are just not set up to allow repeaters to uptrain. They continue to train the routines that they already competed the year before, and not much else.
We uptrain quite a bit, but I think that is what leads people to think a gym sandbags. My DD is doing new level 5, but she has all of the level 7 floor requirements and most of the level 7 beam requirements except the BHS. She should EASILY do BWO-BWO on beam but our girls are not allowed.