He was actually tested at 20 months old as part of early start program (he was 2e back then, had since outgrew it with some intervention),
What kind of 2e was he, and what type of intervention did he have? I'm wondering if what you are seeing in the subtest scatter is potentially related.
FWIW, we have a highly visual-spatial child who also was into Legos etc as a young child. He's older now and quite likely headed into engineering (and has more than a few engineers in his family tree). He did learn how to read very differently than schools typically teach reading, but not having a special program aimed at visual-spatial personalities didn't hold him back from learning how to read, it just happened. He didn't start to read until he was around 5, but once he was reading he was quickly well above grade level.
Re the subtest scatter, my ds is 2e and has significant scatter, and he's also had IQ testing repeated several times at this point. Some of the scatter we've seen under VCI and PRI (in the WISC-IV) has seemed very random - it flipped from his first testing at 8 to another round of testing at 11). He has a larger and consistently depressed coding subtest scores, which is related to his 2e challenge. The only advice I can really give you at this point is that any one test is a set of data from one specific point in time. It's possible the scatter means something, and it's possible it's either random or your ds was simply tired or bored or distracted and didn't perform his best during some of the subtests. What you'll need to do as a parent is observe, and when/if you see any challenges in school (or life) see if there is any correlation to what was measured in the subtest scatter. If so, you'll want to follow up with other types of testing to better understand what's going on.
I doubt that lack of "practice" depressed any scores however. Our neuropsych has shown us bits and pieces of the types of questions asked on this type of testing, and it hasn't struck me as the type of thing that exposure or practice would significantly improve scores on. What *might* improve scores is simply being older, more mature, understanding that it was important to do your best, perhaps a good rapport with the tester etc. I personally wouldn't test again until your ds is a little older simply because it's easy to question results when a child is so young.
Hang in there - choosing a school can be challenging, and our experience was it was truly difficult to know how any school would be for any of our kids until they were actually attending the school.
Best wishes,
polarbear
