LOL, ummm thats incorrect
/me sees the comming "is not, is too, is not, is too"
Tested here and works quite well.
I would guess that when you tested that you saw the results that matched your case becuase the last time you typed in and pressed enter was in that channel, so the $idle was the same as the channel idle. Try it again but change to the status window and enter a command, then return to the channel and check the idle again.
even if what you suggested would be true, activating the timer would also be a command; and the result would still be 0
Since the timer goes off 60 times over a 1 minute period, the $idle value gets evalated each time as it goes off, not at the time the timer is created (note the single / in the command)
Sometimes the first timer event well trip before the $idle value increments to 1 sometimes it doesnt, so you can end up with the first event being 0 or 1 but each following one well be +1 unless of course you type in something (and press enter)