Jen
I had similar issues with DS 4.5 and got some of the same great advice from the same great people, there was one more piece that was crucial for us but of course I can't find my own thread! Not sure what I am doing with that, anyhow, Grinity responded with a method of teaching the pencil grip. (anyone know how to find her description?) It never occurred to me that DS had not been properly shown it and needed coaching on it. He also was very very light, so light the WPPSI tester said she couldn't read some and probably depressed his score. I realized he did not put his arm on the table when he wrote. So now I frequently remind him on the grip and on keeping his arm down, that and some OT and he has made huge improvements. Most important for us, is he is now willing to do it, which he wasn't before, I think the lack of focus contributed to his inadequacies about it.

Good luck, and I second the mommy gut instinct, go with it!!!

DeHe