I'm booked in S class on AF on Aug 1 from SEA to CDG. Called the Delta Medallion line to ask whether I can upgrade to business with a SWU. They stated that "O" class on this flight is not available. A quick check in ExperFlyer shows that it never seems to be available (tried 6 random dates) on the direct flight to Paris. Has anyone had any success in using SWU on this flight? Should I keep checking back (there seem to be plenty of business class seats available for purchase)...will they open some O seats closer in to day of flight?