I am using the Home and Business version of TurboTax, and I have a big desktop computer. I still can't get TurboTax to allow for a subtraction. The Maryland web link you provided tells me that I need Maryland form 505SU. TurboTax did not provide that form.
Another person's question to TurboTax support asks how to add the form, and the reply was that TurboTax automatically populates that form. It didn't do that for me. What would trigger TurboTax to create the Maryland 505SU form? Your mentioned code GG. Where do I enter that?
George Brungot
