While I still don't know if my DD will be moving to L4 or not

She is currently doing 6 hours (actually a little more since she stays late EVERY day). I think that as long as you can objectively watch your DD and see that she is having fun and it is not too much for her she will be fine.
It does take some time to get used to the extra conditioning and longer practices, but once they get used to it they seem to love it. Our L3's work w/ then rest of the team. the warm up w/ the team then the levels split up for training. there are no rec classes going on while the team is practicing except for maybe the last 1/2 hour and on nights when they take the tumbling class (rec kids in that class as well).
Best of luck to you and DD. She will have those splits in no time. You will be amazed. Last night the coaches daughter L8 was working on cast handstands on the practice bar (recovering from injury) and my DD told the coach she wanted to try that so, there she was practicing cast handstands and LOVING every minute of it.
Hopefully soon I can post in the new L4 thread !!!!!