Originally Posted by aa4ever

This is not correct. For domestic flights, with the exception of Y (full fare economy, which clears at time of ticketing), upgrades clear by medallion status and then fare class. What that means is that all upgrades are awarded first to diamonds, then plats, then gold and then silver. However, within an elite status tier, upgrades clear by fare class (i.e. an expensive B fare will clear before a cheap X fare). So if you are a plat, you should clear before any gold except golds on Y class tickets.

I won't deny that DL holds a lot of inventory for the gate to try to sell, but those seats should all be upgraded to if there are medallions on this list. The only thing to be aware of is that once you board the flight, you lose your chance to get an upgrade.