Currency fields and if to get true/false

[Ruegen]

I have two fields which really should be one from an old database.

Both the fields mean that if both are null then it should be false as in not "registered" for tax in a checkbox field that I am appending the IF to

what I have is

GSTOLD: IIf([GSTAmountPaidBankByPerformer] And [GSTAmountPaidBankBySPTours]=Null,False,True)

if both those fields are blank then there was never any tax paid into those fields so the checkbox should be false.

However when I append it doesn't appear as false.

What am I doing wrong?

[Ruegen]

Nevermind, I converted all null to 0 then made it GSTOLD: IIf([GSTAmountPaidBankByPerformer] + [GSTAmountPaidBankBySPTours]=0,False,True)