The difference according to me is where the countdown takes place.
The issue we are discussing is the difference between the session timeout(the server´s timekeeping) and a meta tag which tells the client to refresh after a period of time(the client´s timekeeping). What I´ve been suggesting is that you try to sync the timekeeping between the client and the server so that the client redirects itself after the same period of time that the session timeout is set to.
This is what I thought KryptoS was trying to do. Since there is no way (that I know of) for the server to affect the behaviour of the client between requests, I thought the solution suggested above was a reasonably good one...
Of course, if KryptoS by "doing nothing" doesn´t mean "not requesting a file" my solution will not work, just as you both point out. What you could do then is to use the javascript approach I mentioned earlier, and clear and reset the timeout every time the user causes an event to fire in for example a form. But as I said, that´s not what it sounded like KryptoS was trying to do. After all, the server doesn´t reset the session time just because the user types text in a form field (simply because it will not be aware of it.).