I'm assuming that you have access to the component scores for the literal and inferential comprehension scales, but if not, this scope and sequence lists them:
http://www.laredoisd.org/ERO/ppt/Iowa%20Scope%20and%20Sequence%20brochure%202009%20high.pdfDid you see any kind of profile in terms of component scores that were higher or lower? Sometimes one of the specific components throws off the whole cluster. In my #1's case, it would be the sustained attention portion of literal comprehension that has historically been an outlier.
In individual assessments, I sometimes see students with good higher-level thinking and comprehending skills, but who are either poor word-callers or careless/hasty readers, score better on inferential comprehension than literal comprehension. I tend to think that they show to advantage when performance relies on reasoning, which captures their focus better, versus rote attention to detail, which is, let's face it, just not very interesting. And you can often cover for imprecision using problem solving, whereas there isn't much of a reasoning substitute for brute force remembering the name of the main character or the dollar amount of the purchase.
I wouldn't be worried about his literal comprehension test score, unless you also see corresponding real-life concerns.
