Just tried to stop some timers I've started (using "/timers off"), but there was one problem. They just didn't stop.
After some investigation, I found the reason. The multi-server function of the command doesn't seem to work properly. If i just do "/timers", I see all timers, on every server, but I can't stop timers started from other networks.
And also, note that /timers isn't an index of the help file (/help /timers), but it is documented in /timer.