Thanks for the response, Grinity. AS for his LOG we haven't done official testing yet, just grade level assessments that place him 1.5-2+ years above his age grade.
He LOVES going to the school so I am loathe to take him out of it even though the expense is really difficult for us. The age range is potty trained up to 1st grade, so he isn't the youngest one. There are at least 3-4 others that are older than he is. Once a kid is either in 1st or turns six they have to move on. He's still there because they are turning a blind eye to his "official" school grade. The school itself is a science based school. They actually use REAL terminology and teach kids to look things up! I researched every daycare option within reasonable driving distance to find this place. It really is a good school and a good fit for him.
I just find it very weird that he has trouble finding words to join in with groups of kids at school when he doesn't elsewhere. He's my little social butterfly. Perhaps there are personality issues? I don't know, I just don't know what to make of it. He has friends there and hasn't had any behavior problems... Just odd.