If it is a change (from the UA way), I really don't like it, and I do hope it is announced as a change. I often buy tickets within the upgrade window, based on immediate upgradable space. But if the system works via sweeps rather than immediate clearing, ....

Another factor in all this is that the tickets no longer issue immediately. So if R>0 when the ticket is paid for, but it takes 1/2 hour for the ticket to be issued, R can become 0.