hy a good tool change macro should handle the case of "another" prestaged toolSo having ran a Multus for awhile now I have always hated that if you have a tool pre-called that is different than the tool you want to call next it will alarm out instead of sending that tool back to the magazine and calling up the tool you now want.
it should detect if the tool that you are calling is allready in the spindleOr alternately if you have a tool precalled and you need to Re-run the tool you currently have in the spindle it will alarm out when it tries to pre-call the tool that is already pre-called.
a good code covers shop floor events, not only theoretical ones; i have solved this for mb machines a few years ago, after i saw that shared codes don't cover particular cases; besides what you described, there may be other cases
unfortunately, i don't have experience with multus; you will need patience to fix it / kindly