Can you go and observe for a half day or day. I think there could be a number of things going on, and every kid reacts differently. Sure, he could be very underchallenged and is just getting bored, but maybe the teacher has an unrealistic expectation of behavior. Six months at that age can make a huge difference in ability to sit still or focus (especially on things that are not all that exciting) so I would suggest trying to figure out what is going on.
It just may not be a good fit for your DS, both in terms of academics and structure.
Good luck, Cat
