Originally Posted by
Tokyobuta
I'm guessing, but based on my own op-ups an a mere gold, I think that it may be the number of tier miles in the last year (12 or 13 months) irrespective of individual renewal month.
This actually fits in with my opups within the last year.... got a whole lot more closer to Sept when my Plat upgrade from Gold came up... but very few since then. As far as systems go, this is not really fair.
I remember in StarAlliance that they took your membership number as the older your number, the longer you have been with the program and the more chance of an opup. This would be a more fair system with EK