Just to give my experience with motor skills and processing speed, DS did the WISC IV when he was just over 6. He had had a traumatic brain injury and his eyes were looking in slightly different directions (resolving from when it first happened when one eye was actually stuck). He also has a developmental coordination disorder diagnosis and had issues with motor skills before he was in an accident. His lowest score on the WISC was coding at 50th percentile, so it wasn't as low as what you experienced. He was given a Grooved Pegboard Test the same day, where he was timed putting pegs into a board, and tanked it with a Z score of -4.8 with one hand and -3.69 with the other (these are well below the 1st percentile). It's possible that he could not figure out how to get the pegs into the holes if his vision was bad, but there are parts of the WISC IV which require vision and like I said, his lowest score was 50th percentile. So even though his fine motor ability at that time was atrocious, it didn't show up as an obvious deficit on the WISC (it showed up more as a "relative weakness") and the neuropsych didn't seem all that concerned. He did recommend OT though because of the awful pegboard test. DS had been in OT about 6 months earlier and they had exited him because he improved into the normal range. Then a few months later he was in the accident. All of this being said, if you are seeing fine motor issues in real life, or issues with processing speed, I'd definitely keep an eye on it. DD has slow processing speed (I think she was at the 34th percentile overall on the WISC IV for PS) and it shows up in school as being exessively slow with work and fluency tasks, like math fact fluency, and slow writing.
