Why not import the image or dxf and then use the Tabs on the bottom to display the extents or entity information.
Compare that to what Mach say's about the code file.
I think it's just 1 unit =1 unit and the output code is based on default Mach settings.
I will say this. The dxf has the unit lengths / vector info and LC produces units that are exactly as imported ....so I have not seen some ratio change.
Make sure that you are not scalling any axis in Mach.
That said, you can change the limits in config> limits as the graphics will adjust to suite.
RICH