I don't administer the PDMS-2, but I do know that its upper limit is age 5, whereas the Beery is normed from age 2 through 18+. It may be that the spread at this age range (which is in the upper end of the test range} of the PDMS is not as finely graded as that for the Beery (which is far enough from the lowest ages to reduce concerns about floors, and plenty far from the upper end of the range). The PDMS VMI subtest also includes other hand skills, besides pencil-paper copying; he may have done better with some of them. Given what you report about his motor-reduced spatial ability, it would also have been interesting to compare to the Beery (motor-free) visual perception supplementary subtest scores.
