They have tightened up the rules on Sits this year; it used to be that the buttock (bottom) was to be even with the skating knee; now, the leg has to be parallel to the ice at a minimum, which is generally lower than the old description. I've seen the results in a few competitions - kids are getting called with invalid spins where they were valid last year.
Our test track skaters "get away" with a bit more wiggle room on the issue, however, the competitive track kids - no way. It has to be a true sit.