Could you please clarify what your question is, I'm having a hard time understanding.
If you are using a stepper motor, this is an open loop system and your MT must be set to +/-2.x
If you have a servo motor, it would require encoder feedback and, thus, would be a closed loop system and MT would be set to +/-1.x
If you are having trouble setting up Mach3, Application Note 4428 goes over how to go through some of the set-up procedures:
http://www.galilmc.com/support/appnotes/software/note4428.pdf