Thanks. I've called and the answer is that no seats are available for upgrade regardless of whether it's a preferred or miles upgrade. The strange part is that I've never seen this happen on this flight, so I was wondering if USAir is getting less generous about releasing the seats. Are others not getting upgrades they are accustomed to getting?
I've had no success since the computer changeover at getting them to force upgrades - not that I haven't tried
.