Just curious what's happening here, as I haven't seen it before. Have an award reservation to fly to JFK tomorrow, for me (DM), my wife (GM), and daughter (no status). Called earlier to SDC to a later flight, and the agent was nice enough to waive the $75 fee for my daughter. Nice surprise. The flight I wanted had 3 F seats available for sale, but 8 open F seats on the seat map. Not that unusual, since I assumed several F passengers just hadn't picked a seat yet. After the SDC was complete I asked the agent to split my wife off onto her own PNR. My daughter and I were immediately upgraded to F, as was my wife. Nice surprise #2 . Now that I'm booked on the later flight, when I look at the upgrade list it says there are still 5 F seats available. But the flight is still sold out in F if I try to book a seat on the website. Is Delta holding back F inventory, and if so, why? There are plenty of seats available in Y as well, so it's not like the flight is even close to being at capacity.