Hi,
I would second LaTexican and encourage you to seek out an expert on gifted and twice-exceptional kids, especially if you really feel the scores are not representative of your son's abilities. We had an evaluation this year from an uninformed local psychologist who didn't understand giftedness at all and it was pretty much a disaster from which we are still trying to recover. (Also had a teacher who didn't like DD8 at all, which was the cause of the disaster--hooray, only 3 more days of school!). So we got tentative diagnoses of ADHD, Asperger's, ODD, and dysgraphia--based almost entirely on questionnaires filled out by the antagonistic teacher. Based on James Webb's Misdiagnosis of Gifted Kids book, I don't believe those are correct, but there are definitely issues that we are still trying to sort out. Even if the specialist confirms the test scores you already have, it might go a long way toward putting your mind at ease that you know what is going on with your kid and that you're doing everything you can to help the school address his needs.
Good luck!
(P.S. thanks very much for that link to the arguing article, LaTexican--it explained things very well! We're going to practice today!)