We have had OnTimer Script since FM10. To make it start it is pretty straight forward, you just Install OnTimer script step. But to close it does not make sense. You are doing same script step but sets the OnTimer intervall to 0 (zero) seconds.
My suggestion is:
1. We rename current Install OnTimer script step to Start OnTimer
Parameter for the Start OnTimer
Intervall in seconds
2. We add a new script step called Stop OnTimer
Parameter for the Stop OnTimer
The new script step will stop the started OnTimer script that is running.
I would also like to add a third thing, a function that gives me all OnTimer scripts that are running in current file
I want this new function to give me a list of Names with "¶" as the divider