Flying from SFO to PEK this Sunday 11/24 on UA888. Flight status shows 11/60 seats booked in Polaris and only 15 people on waitlist, so there should be 34/60 Polaris open if everyone on the current waitlist clears (J9 P9). I've noticed based on looking at recent UA888 flights that upgrades haven't cleared until a few hours before departure / at the gate (probably because UA doesn't want to overcrowd the Polaris lounge). Current MUA waitlist price from Economy (G) is $600+30k miles. In the case that there are 30+ empty Polaris seats, is there a chance that the cash upgrade price at check-in time / during boarding is less than $600? Has anyone flown this route (or similar routes like SFO/LAX to PVG) recently and been able to cash upgrade for less than MUA price? Thanks!