AMD, your son is still in K, yes? If so, it's likely that he has not been exposed yet to some of the things on the test and therefore would score a bit lower.
Take Math--if the calculations used unfamiliar symbols he would be at a disadvantage. For example, when my DD6 started working on higher grade level math, there were symbols she didn't know--such as greater than, less than--because she'd never seen those before. But when we explained what they meant, she could easily solve the problems.
I doubt if any of the tests he's taking right now will show his ability to learn quickly and retain that information forever. Definitely a good question to ask the tester.
He's really doing great so far--and you too! :-) Keep us posted!
GG
