You probably know this, but I think it's worth stating. L5 and L6 are viewed as interchangeable by many gyms. In our state, very few gyms compete L5 at all, most go from 4 to 6. Other gyms require both levels, and some require one or the other depending on the kid. If the option is "repeating L5 or doing L6", there is simply not enough difference to worry about it from a progression point of view. Did she do the upgrades at L5? (Switch leap on floor, back handspring on beam) If not, perhaps she can include them this season. What do her casts look like on bars? Is she close to hitting handstand? Improving her casts and the amplitude of her clear hip are additional things she can do while training L5 that will prepare her for L7 (no different than if she were competing L6). I agree with others, find a gym you like and trust them to do what is best for your dd. Then smile and support them. (And come to Chalkbucket when you don't understand something they are doing and wonder if you should be concerned.)
Good point - there are a lot of upgrades she can do in level 5. Beam back handspring, cast to handstand, can also do layout flyaway. Really you could repeat 5 and be a stronger position for 7 the next year with these upgrades than other people doing minimum level 6 or level 6 with missing skills. It's all relative.