Newbie here and I need help! I've for the first time made a bid for upgrade to premium economy on AC 862 YVR - LHR. I did check the seats on Expert Flyer and there are maybe 3-4 seats available. my bid was $600/passenger (there's 3 of us). what are the chances it'll go through? and should I purchase the few remaining exit row seats just in case? thnxx