What determines the clinical significance of a gap is not simply a specific score difference cut score, as many clinicians can attest to having encountered individuals with very striking score differences who have such good compensatory strategies that they are able to function at the level of their highest cognitive skill area. But in answer to your specific scenario, I would say that yes, it is statistically unusual for a child to have differences of that magnitude between scores. And the existence of relative performance deficits suggests that those cognitive differences do have clinical significance. To be fair, the diagnoses he already carries could be considered the interpretation of the clinical significance of his diverse scores on cognitive ability assessments.
On a more abstract note, some clinicians feel that it is more productive to focus on recommendations for remediating skill deficits than on the cognitive testing profile that might be associated with it. To some extent, that is a philosophical or theoretical orientation decision. I take the position that the cognitive profile can inform remediation and intervention approaches both academically and in the rest of life, but I respect the thoughtful positions of other professionals. (IOW, the absence of profile interpretation may be intentional, or it may be for less thoughtful reasons.)
I do also usually look at brain injury a little bit differently than developmental learning disabilities, though, practically speaking, of course, remediation will be much the same. I have pm'd you some additional comments.
