I seem to be having the same issue as described on the AR15.com thread, I am not sure if I can rely on the reference line. It looks fine if it is traced horizontally but the starting and ending points change location if traced at an angle.
Jacques
This has been corrected in 4.0.0.1 but 4.0.0.2 should be a much better version; skip 4.0.0.1.
--HC