I received WPPSI results for DS5 in advance of our IEP meeting today and I have a question about scatter and calculating the verbal composite score.

On the verbal subtests he got:
Information 19
Word Reasoning 14
Vocabulary 4

I was present during testing and during the vocabulary subtest, he was just stuck in a certain frame of mind and didn't want to answer with definitions but rather with which materials and components each object was made of.
However, the report from the school psychologist says that the test is an accurate reflection of his functioning level that day and has several parts about vocabulary being an area of weakness that may require intervention. (Vocabulary is *not* a weakness, believe me)
The psychologist was not receptive to my request to change the report to state that the subtest was not an accurate reflection of his abilities.

Can anyone tell me if the difference in subtest scores in the Verbal section makes the composite score uninterpretable or provide a link?

Also, if I want to play around with seeing what his verbal composite would have been if he hadn't tanked the vocabulary subtest, where can I find a table to turn scaled scores into composites?

Thank you!