There are gyms that do this and make no bones about it. The parents even brag about how their gymnasts, already scoring 38+ AA, will repeat next year and sweep everything.
I thought the post that said most high-scoring gyms do this was interesting. My daughter’s gym is very well-known and does often win, with gymnasts scoring high. But, a quick look at mymeetscores.com will show that they usually move up every year. For example, I know that their level 1 team comes right from classes, and are usually aged 5-8 with the occasional older girl. These girls train 4 hours a week, and they often score 9.8+ , even 10.0, and they train their level and compete it. They do work on level 2 skills after all assignments are done, but none of them have mastered them. When the season is over, they will move to level 2, or bronze, or silver, and train for that level. This is repeated at every level, with very few repeating, and few training higher than their level unless they finish their assignments (with the exception of elite hopefuls).
I said all that to show that high-scoring gyms don’t always sandbag or train 2 levels higher than they compete, they just have a good system and good coaches and it shows.