Can anybody help me with Moshidraw Please?

[Michaelea]

I'm using Moshidraw 2014 software.
I drew a polygon 28mm wide x 26mm high.
When I output it to the laser, it engraves it 16mm wide x 15.7mm high.
So, I drew another one 38mm x 36mm and it engraves this one 22mm x 21mm.
Is there a setting somewhere in the software that is changing the size of my drawings by a percentage or something?
I have searched every tab and don't see anything.
I tried drawing a rectangle as well with the same (smaller) results.
No matter what I draw the output is reduced in size by 40-45%, Why is this??
Any help with this will be greatly appreciated.
Jeff