My DD has numbers along these lines with the WISC IV, although her working memory is a little lower and her processing speed a little higher. My DD is 2E. These areas together affect the ability to retrieve and manipulate information that has been learned (as well as storing it properly in the brain) and then using that information. This impacts her abiilty to do things like math facts quickly. She can process the information but it takes more time to get there and she doesn't always retain it from one day to the next. So she may have learned a math concept but struggles to have automaticity with the actual math facts used in the problem.
It would be helpful to understand if you DS's strength is auditory or visual memory and attention, to see how that might impact accomodations. You might also want to ask if the psychologist thinks that something like perfectionism might have impacted your DS's scores. Is your child bilingual? Sometimes that can also impact processing as one transfers material from one language to another. You would want look at what accomodations they are making for a classroom setting, such as more time to complete tests.
For my DD her GAI on the WISC is more in line with her scores on the Stanford-Binet, which doesn't have as many timed areas and lets her GT show more than the WISC so that might be a future option with testing. This is still a new road for us so I hope you find some of this helpful.
