Is it usual to have a huge variation on subtest results between 2 examinations? My son was tested with the WPSSI at 4 and then again at 5:10. He went from a Bug Seaech scaled score of 18 to 9. In reverse, zoo location went from 10 to 15. All said there were 3 composite scores outside the original 95% confidence interval the second them around, some higher, some lower.

Any info on how to interpret this is appreciated.