Hm. It is possible that the scorer could affect results, but mainly on the VMI portion of it. Visual-perceptual is either right or not (minimal output demands by the child), so it's hard to see that enormous drop coming from scoring differences. Motor coordination has more possibility of scoring effects, but that's the one that went up a standard deviation (still in the average range). This does line up with your previous report that his manual dexterity is within normal limits. The drop in the VMI and VP scores, which actually are more accurately described as failure to maintain progress over the past 1.5 years, are more interesting. To be fair, the ages at which he was tested are such that a one raw score difference can swing the standard score by quite a bit (note that the identical raw score resulted in 36 points of standard score difference when separated by 20 months of age difference).
I'm still thinking about whether that drop in visual-perceptual is meaningful. The recent OT, who did the BOT-2, reported visual perceptual as a weakness. So that's three data points on visual perceptual (by three different examiners, two OTs and a school psych): one is extremely high (2017 Beery:VP), one is average (2018 Beery:VP), and one is "weak" (2018 BOT-2), with the last two occurring only a few weeks apart. That suggests that some factor besides his intrinsic visual-perceptual skills affects his performance. Perhaps fatigue? Size or contrast of visual materials? Lighting? This may be leading back to Portia's suggestion of developmental vision evaluation.
