[MENTION=221202]xenole[/MENTION], thanks for posting links to those threads! Had no idea this was happening, never had issues with seat selection before.
I ended up looking up available seats on AA (looked for flights and clicked on the seats link to see what seats were open) then tweeted AA to help with seat change and they were happy to oblige. I've been able to get changes like adding/removing FF numbers and now seat assignments this way, they respond pretty quickly (under 30 minutes) and are always happy to help.