Tx, your screenshots are for X3 only ( I've never used X3, but all the other X versions never had that tab in the control edit area )
but, you are showing the correct way to do permanent alterations to the
CNC Machine & Control files
using the "Edit" control selection without going into the MMD file will only create alterations for that mastercam session file only. ie deleting the 4th axis to stop having the A ( or B ) address being output to the NC file
-- if you reload the
CNC machine, then any mods are then lost .
access to the Operation Defaults is on the "Files" page of the Operation manager
or
you can just open the .DEFAULT file with mastercam ( D-click on that file --> Open with )
( you may have to "Save as" to have it save with the correct extension )