I'm not sure that is a "drop in performance". We all have strengths and weaknesses. My son's WISC-V results have a similar differences in various areas of ability.
There are alternate calculations other than FSIQ. My son is high in verbal, and low-to-average in processing speed and working memory, so the GAI is more accurate for his abilities than the FSIQ. The difference between his GAI and FSIQ is more than a standard deviation, so this is significant.
Check with the program to see if they accept any other index scores and ask the psychologist to calculate those indexes. It's worth a shot for just 4 points.
