My hunch is that if he looks focused to the teachers at 7, when there suspicion is the highest, that you won't have that issue, but of course, it may be crop up.
I know that girls can be different in this regard but our DD is described as very well behaved and focused at school - what that means is that she is pouring every bit of energy and mental focus into behaving appropriately and is unable to process the actual education at all... It's intensely frustrating to be part of but in general she is thinking harder and learning more the more she is moving. Which is to say the harder she needs to think about something the more she needs to move her body while she processes it.
Edited to add: We had to work very hard to stop telling her to sit still while trying to learn to read and instead remind ourselves that she was not being difficult or disrespectful.
