I think no matter what system you're using, you have to work out something where the child can either get help from the teacher or back out and bring it home. DS had been using ALEKS in the classroom up until January. When he needed a different explanation than the one in the program, his teacher wouldn't help him. He brought it home and I explained it, he moved on.
I didn't know at the time that just the mere asking of the question proved the teacher's case that he "can't" work independently. She has since prohibited him from doing ALEKS at his level in class and has moved him to Accelerated Math. (Which despite the name is not accelerated...think Accelerated Reader).
Just make sure you have a plan that everyone has some level of buy-in!
