I did that and when I tried to bring the drawing and xref which I used to build the model in revit, into the autocad, they do not fall at the same place. When in fact I used that xref cad file as base. I tried also without scaling, it does the same thing. It is very important for me to have Revit export the drawing with same coordinates so that when I use both xref and revit exported model, they fall at the same place.