Good Move Mabay!
((I'm also an ENTP - married to an ISFJ, LOL!))
I'll also reccomend the "parenting self-help book" Five Loe Languages of Children
http://www.amazon.com/Five-Love-Languages-Children/dp/1881273652simplistic by worth a try -
Can you son's private school try accelerating him in one subject? Have you had your son tested for IQ, talent search or Woodcack Johnson Acievement levels? Did the private school do anytesting? I'm sceptical of "social immaturity." Maturity means so many different things to so many different people. Yes I have heard that ADHD tends to go along with less maturity, but what exactly are the school's complaints? Is he hitting? Crying often? Disrupting the classroom in some way? If you kid is going to feel like a Martian socially (I did, it's not pleasant, but you learn some important lessons that way.) then he may as well be in a situation where he is challenged academically.
If you haven't read "Re-forming Gifted education" by Karen Rogers it's worth a read - just to see what all the wide variety of options are.
Hugs and Best Wishes
Trinity
