Hmm. I think the OT at school ruled out dysgraphia, but I'll double check with her, and will mention it to the private OT we're going to go see as well. I've - just now, after reading this :-) - done a tiny bit of looking it up, and while he has some of the symptoms, others he does not (he does take pride in his artwork, unusual as much of it is; he loves and does very well with Legos and such; his spelling is fairly good, although actually better spoken than written, so that may not count!; does well with some forms of creative writing, especially poetry; and *can* write neatly when he is watched and regularly reminded to focus on it). All that said, there are a lot of things that suggest he might have that problem. Certainly worth looking into!! Does typing work for dysgraphic kids?
I think you are right about there being a difficulty of getting words/thoughts out of his head rather than just frustrated b/c he can't think of the answer. While he very clearly has timed task issues, he also has trouble getting things out of his mouth when it isn't timed, and again, its clear that he knows the answer. It just doesn't come out quickly.
As for testing that looks at why there were such discrepancies, they didn't do that, no... I didn't really know enough, I guess, to push for that. Wish I'd done this research before the IEP meeting!