This is not what I meant. Time of being a QFF member ONLY is of relevance if while working through the status category and down the fare buckets ie W,T,Y,B etc etc down to lowest upgradeable fare class, there is a tie - For example:
Lets say the computer works through all the Chairmans Lounge upgrade requesters down the fare buckets and then repeats this for the Plats and then in turn for the Golds. Then it starts on the Silvers.
Lets say there is one silver member with a premium economy seat in "T" class - he/she gets an upgrade to J and there is 1 business upgrade seat left. Then for arguments sake the next 2 silver upgrade requests are at the "B" economy bucket. However, there happen to be 2 separate passengers, both in "B" economy seat buckets and both seeking an upgrade to business.
So there are 2 silver members both with "B" class economy seats and only 1 upgradeable seat left - in this instance the upgrade will go to the silver member with the lower QFF number (as they joined before the member with the higher QFF number).
To reiterate, time of joining only becomes relevant if there is a tie at a status level on the same fare bucket. If there is no "tie", time of joining never becomes an issue.