No one knows the exact answer to your question, but in my experiences over the last couple of years, I've found that Revenue Management has probably become more sophisticated about the timing of the release of seats available for upgrade from WT+ to CW. A couple of years ago, I found that seats were generally available, and if I was traveling by myself, I even had the luxury of holding off on an upgrade while I pondered whether I really wanted to expend the extra cash and Avios.

It's different now. I've never booked flights way in advance--I'm not making plans for flights in January 2014 right now, for instance, so I can't say what the availability is or was like 11-12 months out. On my closer-in booking window, however, I've noticed that upgrades are generally not available when I book the flight into WT+ but may become available, and on a haphazard basis, as I get closer to my flight dates.

This past November, I flew from IAD to LHR. I had booked WT+ for two but there was no upgrade availability when I booked the tickets in mid-October. There was also no availability over the next five weeks. And then about 36 hours before my flight, two seats were available. I made the booking immediately because I didn't trust that the seats would remain available.

Revenue Management comes into play because, under my theory, there are four general classes of folks who are buying tickets: those who will pay full price, those who will buy on a sale, those who will take the cash upgrade offers at the time of booking, and those looking to redeem Avios. From BA's point of view, they love the first group, hunt-and-peck with the second group to determine what's the magic price point that will get the seats sold, are probably happy with the third group, and turn to the redeemers as a next-to-last resort (cash airport upgraders being the last group they hope to use to fill seats).

Under my theory (uninformed by any inside information from BA), I believe that UuA is still viable, but I no longer assume I will get the upgrade I want. I buy during WT+ sales figuring that I'll get a seat I can tolerate at a price I'm willing to pay for the possibility that I can upgrade to CW before my flight. That thought process informed my purchase of tickets to FCO in March. I've checked upgrade options daily, and there have been none--but that doesn't mean there won't be some openings before my 3/14 flight.