Originally Posted by 3Cforme

I don't believe that's true. From AA.com:

Q: If I pay the co-pay will I have a better chance of confirming the upgrade? Are you making more upgrade seats available?
A: The co-pay is not collected unless the upgrade is confirmed, at which time miles are deducted from your account. Our Revenue Management analysts constantly monitor our seating inventories to ensure that the maximum possible number of seats are available for upgrade, given our primary goal of selling our Premium services at full Business, First and Premium Class fares. The addition of a co-pay does not alter this procedure.