First of all, judging your child's dance ability based on festival results... BIG MISTAKE!
Festivals are not a reflection of how good or bad your child is, or how ahead or behind other children they are. Most children need time to gain confidence and experience of doing competitions before it starts to show in their results. My children usually do 2 or 3 festivals before they hit their stride and start medalling. It is a common mistake to think that just because your child goes to a good school, that they should go into their first competition and come away with the gold... but that really doesn't happen that often, trust me!
And don't forget that it's the adjudicator's job to highlight technical faults. That is not a reflection on the dance teacher either, it's simply a case of, on that day, at that time, the adjudicator spotted that technical fault. As a dance teacher, I quite enjoy getting the report sheets back from festivals, because 9 times out of 10, they spot the exact same faults that I have to correct EVERY SINGLE LESSON!!! We can teach it, but sometimes the kids only listen properly when it comes from an adjudicator.
On the subject of double schooling, it is an absolute no no for nearly every dance teacher I know. Unless you are talking about associate classes etc, it's just not the done thing. Some teachers will allow a child to go to a class elsewhere if it's something they don't offer (I have one girl who goes elsewhere for ballroom), but as a general rule, most dance teachers don't allow it. Unfortunately, it's happening more and more nowadays, usually behind the teachers back, which is incredibly insulting. I recently discovered on of my Grade 3 ballet students was also attending a Grade 4 class at another school. The mother said it was because she thought her daughter "needs to be pushed more". It turned out that being pushed more meant my carefully taught, 9 year old, 100% Distinction student being put en pointe way before she was technically ready for it. I didn't give the mother a choice... she was GONE... shame to lose a good kid, but there's always another one will come along to fill up the gap.
Now please don't take this as a lecture, BUT, I wish parents nowadays would just STOP looking sideways at other peoples children, and getting jealous over insignificant things. Every child is different and progresses at a different pace. Could your child be pushed on a little more, perhaps, but is that fair on the rest of the class who need more time to develop? NO! Is it going to harm your child to go a little slower? NO! And if the teacher is good and thinks your child needs pushing more, they will make it happen, but remember, that usually means private lessons that most parents don't like having to pay for. But dance teachers are not superhuman, we only have so many hours in the week, so cut us some slack PLEASE!!!