The errors are in the original file. I think you will have to come up with a compromise in the form of a mean error value and scale the converted object using that scale factor.
Meaning pick key dimensions in all directions and determine how close they are to the actual listed dimension. Add all those up and come up with a mean and scale the original converted file. That will bring g them all to as close as you can get without redrawing the objects. As it is a civil drawing and it is not uncommon to have a +/- distances associated with each listed distance, it's not like a wheel walk was performed for each distance listed. You could also double check some of the distances with google earth, a virtual wheel walk (unless this area does not exist,
have not looked at the objects in detail).
Best Regards
-Tim C.
