My DD has a 70 point difference between some of her scores.
Her GAI is 170 (WISC extended norms) and her Processing Speed was bang on 100. I can't remember, off hand, the full scores though her GAI without ex-norms was 157.
For DD, she scored far higher GAI wise than we imagined as she always seemed to struggle to get an answer out, seemed to think for hours or just look blank.
Our Ed Psych suggested looking at ADHD so we went down that route.
My son's WISC-IV scores at age 7 were this way too--GAI with extended norms was 60 points above processing speed. Without extended norms it was a 55 point difference. I think his main issues with the processing speed subtests were a combination of poor fine motor skills and a lack of motivation.
