BB, there are only a few supported Formats for output. As far as I have been able to test, you cannot Set this in the Formula, but only in the Format Type. These Types are: Text, Integer, Real, True/False. I have tried this, which I thought would work, to no avail, I can get other properties, but no coordinates.
On Error Resume Next
Set oApp=GetObject(, "AutoCAD.Application")
coord = obj.Coordinate(0)
I have no clue why they went with quasi-VBA for the formulas. Note that they don't require the Dim xxx As xxxx