I'll second aeh's suggestion of a fine-motor/OT eval. FWIW, his symbol search subtest is high (95%)... and that's a subtest where a student has to identify a specific figure in a field of multiple chaotically arranged figures - a bit like looking for Waldo. Coding (under processing) requires a student copy strings of specific directional markers, which is a task that relies on both visual and fine motor skills. Both subtests are timed... but the disparity between SS and Coding *might* indicate a fine motor issue.
One thing you might want to do is google "WISC-V subtest descriptions" - and read through the description of what each test is and how it's administered, then compare that with subtest scores and what you see in your ds' life - looking for any explainable correlations.
Best wishes,
polarbear
