One additional "twist" should be considered. When the automatic upgrade procedures were put in place I recall that priority within an elite group was to be based on the timing of tickets purchased (earliest purchase = priority), not on cumulative mileage in one's AAdvantage account or price of the ticket. However, I experienced several occasions where the flight number or routing was changed and the request "fell out of the queue." When the request was resurrected, I was unclear if it related back to the purchase date. I also had an inkling that price of ticket may have snuck into the criteria.
In general (about 90-95% of the time) I have been able to get upgrades for me and my wife (also platinum), but it is much more difficult to get the confirmation "from the getgo," when the 72 hour window opens.
Any further insight?