door dimension marker incorrect dims

[heathldesign]

could someone please explain why my door dimension marker is not showing the correct dimensions. i have set the door nominal sizes to unit size and the size is correct, i have set the dimension marker content to show unit dimensions, but the dimension marker is subtracting ½" to the height. see pics

ok, so the ½" difference seems to be a rounding issue. if my unit is set to 7'-1" it shows the same, if i change the unit to 7'-1 ½" it shows 7'-2" if i change the unit size to 7'-2" it shows 7'-2". is there some specific dimensioning resolution that the door / window tool can be set to separately from the dimension in project prefs?

[BrunoH]

You set the Tolerance to 1/2" so the door dimensions are reduced by 1/2"