Hi all, I'm looking at doing a trip to Mainland China and with award availability still being pretty non-existant (on USA routes at least), I was curious which airlines reliably offer cash upgrades from economy (or premium economy) to Business Class, at a rate LESS than the fare difference between the two? Hoping for something in the ~$500-1000 range each way, as Xiamen Air reportedly used to offer ~$500 o/w cash upgrades from Economy to Biz but I don't see that on their webpage anymore