Slightly different situation, but let me tell you a story, Kelly, about my brother-in-law as a child.
There was a situation where my BIL was deemed to not be intelligent because he followed all the rules (go figure – they were written on posters on the walls, and he could read them, and followed the rules). After realizing this at a parent-teacher conference, she came home and told him, “Jeff, I know this is going to sound really weird to you. But tomorrow, I want you to go to school, and break all the rules. You don’t have to wait until you’re called on to answer, you don’t have to stay in your seat. Don’t be really bad or mean, just don’t worry about the rules that are only on the walls.”
The next teacher’s conference, he was the brightest child in her classroom.
Maybe your son needs to be given a little permission to *not* hold it together 100% while at school. If he’s not putting so much energy into being super in that environment, a) that alone might help him in the home environment, and b) if that doesn’t happy, they’ll at least see some of it, too.