In regards to the medallion status complimentary upgrades: in the fly delta app I can see the upgrade list. It shows how many seats are available in first and comfort. Does that mean if I had status and was in the appropriate window (silver >24 hour), I would get that first class seat?

I’m reading the upgrade success thread and I see people mention I’m 3 of 5 for 4 (or a different set of numbers). Does that mean there are 4 first class seats available, 5 people wanting for upgrades, and this particular person is 3rd in line? Why haven’t they been awarded the upgrade already if there are 4 seats available?