ETA: Oops. Just read your other post. If he's entering third grade, he should have been scored on the Grade 2: Spring norms. Deleting the non-relevant portions below.
July should be considered the spring of the previous grade level. E.g., if enrolled in grade three during the 2016-2017 school year, a test administered in July of 2017 should be scored using the Spring Grade 3 norms. The same test administered in August 2017 should be scored using Fall Grade 4 norms.
(deleted) However, aptitude-achievement discrepancies are always supposed to be calculated using age norms. (deleted) And the score summary would not say anything about grade-based scores at any time of year; it would say "Age Based Scores". Also, in order to do the discrepancy, the examiner would need access to WISC scores obtained within 6 months of the WIAT scores. (And I should note that the field continues to have discussions about the appropriateness of using aptitude-achievement discrepancies for identifying specific learning disabilities.)
If your school district uses a different model of identifying learning disabilities, (RTI/dual-discrepancy, pattern of strengths and weaknesses, etc.) then the appropriate norms used for purposes of disability eligibility may be different.
Last edited by aeh; 08/10/17 12:21 PM. Reason: wrong grade
