Agree with everything above.
I guess one way to look at is this: If your children were BEHIND to the extent that they are AHEAD, would you be scheduling a meeting?
Actually, probably not, the school would have already called you to discuss it.

I find this comment pretty troubling:

Nobody knows how full of facts this child is, and when he shares something, they are shocked. The reaction puts him deeper in his shell.

Especially: The reaction puts him deeper in his shell.

Just that is a valid reason to pursue this, IMHO.