Okay, others may disagree, but I think this just helps "prove" the flakiness of IQ tests. I think this also proves he is extremely strong in both key areas (verbal and perceptual). He is solidly in those very top percentiles. Who knows why parts were lower in both sessions...I'm not sure it matters. His scores overall are excellent!
I'm going with Dottie here, which always seems to be a good bet

!
My youngest was tested twice on the WISC with a similar weird range on PRI. The first time her PRI was in the 99th percentile and the second in the 75th. Her VCI didn't vary so much though (99.7th and 99th).
I don't think that the psych's comments about the changes not mattering b/c the overall # is about the same is legit, though. If both of those scores are "correct" his innate strengths and weaknesses are quite different than they were two years ago. We were told that dd's drop in PRI was due to "fluctuation in ability." Achievement fluctuates. I'm not sure if ability does. I'd be more inclined to agree with the others who have said that he is very strong in
both areas.