I personally wouldn't want to spend a year training L3 skills if I was going to compete Xcel Bronze or Silver.
Do you have videos of her routines at meets? If so, maybe she should watch them and see if SHE can tell you what is wrong. If she can, then there is no need to go back to developmental.
If she knows what is wrong, she can:
1 - determine if it is something she can fix on her own (straight legs, pointed toes, tight arms, etc).
2 - determine if it is something she will need help to fix, in which case, she should advocate for herself and ask the coach for constructive feedback, spotting assistance (to "feel" the position she should be in), or drills to work on.
3 - pick one or two things on each event to work on to get it to be muscle memory.
4 - condition at home (maybe get a list of conditioning exercises from her coach). Our girls who condition at home have more stamina and are able to be "tighter" in practice and at meets.
If she DOESN'T know what's wrong, then I am 50/50 about going back to developmental ... but only IF her coaches can't figure it out either AND if that is what she wants to do. It is possible to score well AND be in a fun environment. We have 2 girls that competed L3 last year and L4 this year and are scoring in the 36s (usually in the same age group and taking 1st and 2nd in the All Around) ... and we only practice 7.5 hours a week, 42 weeks a year.
Definitely, have a meeting with the coaches (without your daughter present) and see what they say. They may not realize that she would like to be pushed a little more. See how they feel about her taking the year off to get the developmental training at the old gym. Maybe see if there is a way to do BOTH (would need both gym's permission and would only want her doing 2-3 hours at the old gym, depending on how their schedule breaks out, and if it would work with the current schedule).
Good Luck.