In 5.0.6 I was able to select a new tool F4, click auto tool zero, and it would go through the motions of zeroing. In F2 it would list this new tool as being loaded.
In 5.0.7 however, it complains about “tool not loaded”.
It appears that you can use the MDI command window on the G3 Masso controller to prompt the machine to load a tool by using a “T” command and an M6 command. For example, on the command line, you can type T4M6 and then run. The machine will move to the manual tools change position and prompt you to change the tool, which in this example would be tool number 4.