What is the GAI from these WISC IV numbers?
or can I at least figure an estimate from these numbers?

My son is 8 years old. The test was given when he was 7.2yrs old.
info-22
comp-14
sim-18

bl.design-18
matrix-17
pic.con-17

Here's the link to the report with the GAI translation table:
http://pearsonassessmentsupport.com/support/index.php?View=download&EntryID=353

I came up with my own number of 157 with extended norms, but I'm not sure why the GAI was not originally included in his report, especially when the discrepancy between the PRI and PSI is found in less than 1% of the population.

Are the categories tested not the usual to determine GAI?

Obviously my GAI is not very high because this is really confusing to me.