Yesterday I was attempting to create a yes/no parameter for visual panel of the fire rated door, However, Revit doesn't have a visibility for void extrusion, there are a few methods I discovered in the internet, one of them can be found at Revit Nightmares Blog
which is simple to use the following formula
IF (<condition>, <result-if-true>, <result-if-false>)
I have posted the query on forum to find out more about the "Inconsistent Unit" Dialog, Apparently there are other methods to make it simpler, I will post more on my findings.
Using 1, and 0 with 1=1, and 1=2 (assuming 1 to equal true/on and 0 to equal false/off)
Will follow up again, once i figure out more about it.