[OR IR] Drafting Notes using Equations - Confused by Supplemental Text using Parenthesis

I am trying to annotate a Top of Curb, Bottom of Curb using a single note, where the user selects a point on the DTM at the Bottom of Curb and the Drafting note performs the math.

I can get that to work using  ({ELEVATION_ACTIVE_SURFACE}+(8/12)) but I wanted to add a (BC) and (TC) to the elevation text. While the one elevation works with the added text, the other elevation that requires the equation in the parenthesis, apparently gets confused and generates the label using the RAW text string instead of performing the calculation.

Is there any kind of Escape character that can be used to override a parenthesis from consideration as part of a calculation.

I even edited the file in Notepad++ where I tried to use (TC) but the result was the same.