I agree with ConnectingDots regarding the dubious necessity of homework. I definitely don't think it should be used as a measure of the appropriateness of your DD's education. During the year of worst educational match for my DD she had assigned homework each day... boring pointless busy work that just highlighted how much her education was not working for her.

I think you should focus instead on what study is going on in class and what she's learning about learning. If she's at the ceiling on every test and just coasting, then yes, maybe a skip is warranted. But it could also be that the school just does a great job with the in-class learning and she's getting a ton of benefit. The son of close family friends goes to an excellent school, very rigorous, great scores, sends multiple graduates to ivy's, and they don't really have much homework. They do however have very engaging, involved curriculum and great support for the kids' learning.

If only they weren't so anti-acceleration, we might have tried it (it's really a lovely school, but still just not 'enough' at our DDs grade level).