Changing the Dimension format before dimensioning exterior walls does not seem to be working for me. For example, if I have it set to "Surface" and then dimension, it always dimensions from the stud. No mater what I set the format on it always dimensions from the same place. I tried all the selections. I'm using 2x6/siding as my wall.
I also tried changing the format in "Dimension Options" in the "Drawing Options" area and got the same results.
The interior wall format works fine.