Originally Posted by
u600213
Recently on a 3 class 777-200 I got my GPU upgrade of W fare at 36 hrs before flight but only middle seats left. At ORD Polaris lounge I asked about buying an upgrade to F. I figured free to ask. Anyhow, I was offered $600 and 30K miles. I would have done it but the computer would not let them take my money. F was empty. The nice Polaris lounge person called the gate and asked them to get me an aisle seat if it became available. So at gate someone got upgraded to F and I got their aisle seat. I was satisfied with the outcome.
Last time I did a double upgrade, to fool the computer, the agent had to do the double upgrade the other way around: first the buy-up, then the mileage/instrument upgrade. This was because the buy-up can go into a revenue bucket in business (usually P) and the computer can mistake it for a paid business fare whereas an upgrade will be in R and the computer will know it is an upgrade and won't stack a buy-up on top of it. It worked for me in the past anyway-- I don't know if they have since tightened things up.