That's a great use of those snippets of time. I have to say, that wouldn't work for us. We home/virtual school, and what works for us is to focus on a single subject on any given day, and get through a few weeks curriculum in that one subject in one sitting. We find that is highly efficient time-wise.
It sounds like your school is not coming to grips with how much acceleration some kids need. His true level may have permanently "lifted off" from what the school is willing to offer, so the real learning will happen at home.
