I'm still using the work-around. However, I happened across another occurrence of the same issue and thought I'd post it just to shed more light on what might be going on. 

=SUMPRODUCT(--(INDIRECT(AccountType)<>"Withholding") )
This returns a value.

=SUMPRODUCT(--(INDIRECT(Categories)={"Transfer","Pets"})  )
This returns a value.

=SUMPRODUCT(--(INDIRECT(AccountType)<>"Withholding"), --(INDIRECT(Categories)={"Transfer","Pets"})  )

This results in a #Value! error. Also, each individual function, when entered as a stand-alone statement, returns a higher number of occurrences than there are possible rows in the defined array.