SD for subtest scaled scores is 3. A difference of 3 scaled score points between those two subtests is on the line of meaningful difference. I wouldn't focus on the percentile difference too much, as percentiles bunch up in the middle of the bell curve. I don't have my reference in front of me, but if I recall correctly, 3 points is statistically significant, but, again, not rare. In any case, the meaning of score differences should always be with reference to actual function.
So both core reading comprehension scores were lower. That tends to make the generally lower reading comprehension more believable as a real result, and not just due to test anxiety (which you would think would affect other subtests, as well--so even if there was some score depression due to anxiety, it still means something that he had that much more anxiety about reading comprehension than about other academic tasks). This finding is a bit more suggestive of an underlying language deficit, rather than an auditory processing deficit only.
