I ALWAYS put myself on waitlists for upgrades as the flights I want are NEVER available for milage upgrades. I normally ask about the upgrade process at the end and I have been told DOZENS of different things, from the fact that your upgrade could clear right up until the flight to the fact that it drops off 3 days prior to the flight and all in between. Needless to say, I NEVER get an upgrade when I am on the waitlist if it hasn't cleared before the platinum upgrades start to hit. PERIOD. So I ALWAY ask them to take me off of the list and refund my miles and they NEVER charge me.