So, I've tried a number of things and still cannot get it to bring in to the correct build size. This totally makes Simplify3D useless to me for replicating anything with accuracy. I am including screenshots to show the MAJOR discrepancy. Maybe it's user error on my end...
This is a shot from 3DS Max with the information of the object. I have made a build area that is the build area of my MakerGear M2 (200mm x 250mm x 200mm). I then moved all my items into the area in 3DS Max, scaled them accordingly to the build space and arranged them. I reset the Xform so as to reset the scale to 1:1 as to make sure there are no mis-scale issues. You can see in the screenshot that the object's dimensions are X:125.884mm Y: 154.717mm and Z: 197.933mm. These are well withing my build area's volume.
I export as .obj since 3DS Max will not export .STL with the "Export Selected" option. It's either all or nothing and I haven't taken the time to break the 18 items into individual .max files. Upon importing to Simplify3D I get this:
I've looked through the options in S3D and tried a couple of things but it's always the same result.