I can't answer your question specifically. maybe aeh can comment about the technical aspects. We used the SB V but DD was 7 and 9 during her testing. I think your questions re the scores and new tests versus old test are legitimate but ultimately you want the test that gives you the best information about your child and their needs. We are glad we went with the SB V but we haven't done any Weschler testing so I don't know what information that might have given us too.