Originally Posted by
ranok
Perhaps I was unclear: I had 2 RPUs expiring 1/2016, used two in 2015, reached Plat for two more RPUs (actually 1K, but those RPUs/GPUs haven't hit yet), now I have two RPUs, one expiring this month, and another next year. I would have assumed that redeeming RPU would use the oldest (i.e., closest to expiring) before one of the new ones.
Yes, they are applied in age order but once it is applied, that specific instrument stays with the reservation. If you book another flight earlier and apply an instrument, it will take the next available instrument in expiry order even though the flight may be earlier than the other one.