I think the third grade version changes from being picture based to the child needing to read the test on their own. So it could be showing simply that your child does better on certain versions of the test. My DD was the opposite. I don't have her Kindergarten CogAT scores but I know she was highest in non-verbal and her overall score was high enough that they allowed her to grade accelerate. Then she took the third grade version in second grade (they used to give the kids the test for a grade level ahead) and she had problems with the timing bringing down her scores dramatically. That time her verbal score was the highest and it had been the lowest on the K test.
CogAT is not reliable but even real IQ tests aren't necessarily reliable in young children.
