Is there a miNUTE measurement difference between linked file and project file even base point and survey point is same

Hi Guys
i have a Question

I created a sample model just with walls ceiling and floor and created a room in arch template
I switched on room bounding and got the elements associate with faces of the rooms using python
particularly the bottom face associated with floor

when i tried the same in creating a room after linking that same model i did not get any bottom face