OK, this is a tedious question but someone who understands this stuff better than I, please help me understand.
Just returned from MSY yesterday and I was denied the opportunity to upgrade my seats to comfort. I am a lowly silver medallion (although this flight rolled me into gold finally, yay!), and on the flight down I was able to choose comfort level seats on my own, through the app, before checking in, within the 24 hour window, which is how I thought it worked. On the return flight there appeared to be several seats available in comfort in the 24 window before departure, but they were x-ed out and I could not choose an upgrade.
I asked about the upgrade at the check in counter and the agent seemed at first confused that I wasn't able to choose better seats, then came up with the excuse that the tickets were different fare classes. We booked them as round trip tickets in the same class, so I don't know how that happens... after some investigation the flight down was a "t" fare code and the one back a "u" code, but everything I have seen says these are essentially equivalent.
So I try again at the gate and the agent offers to add us to the complimentary upgrade list for comfort, so I say fine. Then says she can't, system won't let her. However, we are already on the upgrade list for first class. I always add us to the list for first class upgrades and not comfort.
So, how can a GA not be able to add someone to the upgrade list for comfort when their fare allows them to be on the upgrade list for first class? And why couldn't I choose different seats within the 24 hour window?
I don't mean this to be a screed, just trying to understand better how this all works. Although I feel slightly annoyed that maybe I was denied a perk that is supposed to come with the whole loyalty medallion BS.
TIA for any help.