Originally Posted by
skimple
What was the fare class of your purchased ticket?
Fare paid does not matter when it comes to the REVUP program. The fee to upgrade is fixed based on the day of the week, city pair and direction of travel. It is a great deal when it is available but you are taking the risk that it will sell out in advance, at which point you are stuck in your coach seat.
The fee schedule is buried in a thread somewhere here and also
here.