my take on the scores..i would say the scores are very good considering your DS4s circumstances. His lower processing speed is pretty common among the GT population, but could also be a result of fatigue..The 133 and 131 show a moderately gifted child...
as frustrating as it is, i would forget about the child pychologist and focus on the preschool teacher, as she is the one who will make impact on your son. He probably could use lots of enrichment within his classroom. Also, does he go full or half-day?? i found it very interesting on the kindergarden thread that so many of us like half-day school for their kids because they don't get too exhausted and there is still time for home enrichment. That might be ideal as your DS4 likely has stamina issues.
Also if he is interested in math and doing academics, you might want to look into one of the online programs such as EPGY which can deliver a lot of content in a very efficient/not time-consuming way. He might be too young yet though for that.
Also, are you familiar with montessori? my dd5 used to attend a montessori and the atmosphere was very relaxed and seemed less tiring for the kids than traditional preschool. For example, lying on the floor to do work was ok..
irene