I'm no expert but most of what I understand seems to indicate if you are looking for clear log answers from a WPPSI or a WISC it is going to depend on the assessors abilities to read between the lines since neither tool was designed to do more than id gt (or problems). I think scores 3 deviations+ are guess work. And if you look at some of the case studies listed in books you'll see a lot of kids jump from scores in the 40+ to scores 160+ ... I think in the end it is finding comfort with knowing mg/hg/eg/pf and not stressing about the number (although I get for some programs or some adminstrators it makes communicating easier).