I have noticed that in certain cases, if the subtractions will fit on form 502 (note the four spaces for codes on line 13), then form 502SU is not added to the return by TurboTax. I imagine that with as many returns as TurboTax does, if the state of Maryland did not like this, the state would have said something.
Note that since the codes are on line 13 on form 502, then putting the same code (<=4) on form 5012SU would seem to be redundant.
Does that cover your situation?
