I think we would need to ask the programmers what the "trip" is for turning off the clock.I would have thought it would have been an M30 command - but it isn't, because when running programs with several "parts", seperated by M1 holds, the clock seems to time each section seperately.
If you are saying it is the M5 command, that would be it, becasue I have that before each "stop" to change tools etc.