Here are my thoughts and I hope that they help you.
So, the 135 GAI should not be disregarded. Also, don't feel like you have to qualify it because it is not 'off the charts.' Think gifted or not-gifted - better accommodated in gifted classes or non-gifted classes. Someone made a specific decision to make 130 the cutoff; it has to be based on something (when I get a chance I want to research this for myself; it might be in the legislative history of the different state statutes). It may just be that represents the top 10% say for cognitive ability in any one class by grade level.
When you mentioned that specific other test I read a few sentences about it on Wikipedia, which has a criticism listed that something about that test (maybe it was new and they were working out the problems) could lead to unusual high or low scores. That is definitely worth looking into; you might help fix the problems and that can help everyone.
Then, I remembered that test might have been the one that was picked-up and discussed by the press - major magazine article (New York Times ?), radio discussion and even a small amount of television coverage. Parents were very definitely prepping their students for that test. It came up before on this forum and I remember thinking, okay, if you orchestrate your child 'passing' a gifted test, isn't anyone going to notice (especially that child) that the child isn't thriving in a gifted environment or is the parent going to force the child to work extra hard just to keep up - not a good idea for the happiness factor.
Your child is so lucky that you are aware of everything that is going on, following up is exactly what a gifted adult would do (We are constantly trying to figure everything out correctly.) Not everyone will enjoy your questioning, but hopefully they will respect it.
