Check your units.
If you toggle true scale on and off in the reference file dialog box, does the scale change from 1:1 to something like 1.000002:1 or 1: 1.000002 ?
If so, it is a survey feet vs ft issue.
Also, in Civil 3D, the default units are international feet. And while MicroStation does not "see" the Civil 3D units, it does attempt to resolve the units as file are opened. You might have to specifically set the units to survey feet instead of feet.