Honestly, I may be out on a limb here, but if he says school is fine and school say he's fine (is that still the case?) I wouldn't personally be messing with school right now even if I did feel that in the long run he needed more challenge there. I think it's worth a lot for anyone to have part of their life where things are smooth and they know how things work and it's all OK, iyswim.
I know you've been thinking already about changing things at home, but still... Fewer or different activities? Earlier or later bedtime? Different snack? Ban or limit computer use on weekdays? Dedicated one-to-one time with a parent?
