AFAIK - expressions return values in calculation units. Within a expression, you can use any units you like and it will make the conversion(s). I believe the number unit selection will not add comma separators unlike the length, etc. measurements.
The problem is that Archicad currently has no currency format available. The work around (and not a good one) is to use a Python script to do the calculation and write a formatted currency string to a user property assigned to the element(s). The expression is not used but a Python script requires a manual update. That may be unacceptable but still would be easier than using Excel
Gerry - Python perhaps easier than Excel.... unless you don't know the first thing about Python 😂
Barry - yes - Working Units will control decimal precision of those "unitless" numbers. So the software hook seems to be there. But does anyone *ever* need SF calculated to four decimal places? Silly. I'd rather have the "precision" in reports to distinguish currency from area, for example. With different decimal precision for different units...
But we need less of a sledgehammer and more of a scalpel. Better to have format control either within the expression itself, or at the level of a column in the schedule. Blanket settings for "all numbers, everywhere" ain't that helpful.
I am at the same juncture, but with trying to creating a label that reads the zone SF, but would prefer to have the comma included, after using an expression to round the sq ft number to the nearest whole number.