This is subtle but RME changes how the size of a duct is listed in the tag according to the view orientation of the view that you place your tags in. In plan you get this for a 36" wide x 24" high duct.
In elevation/section however you get this for the same duct.
This convention is defined by the practice of listing the visible (what we see in the view) dimension first. In plan width is visible so it is first. In elevation/section the height is visible and therefore first in the tag values.