Our tester submitted a written report in which she stated why the FSIQ was not the best estimate of ds's abilities and why the GAI was and she calculated both scores.

I would ask your tester for her opinion and for some written elaboration.

Your ds only needs one score above 145 to qualify but if your tester is willing to calculate the GAI. I believe that's done when there's more than two standard deviations between indices, but I could be wrong. I don't quite remember off hand...