So I got RUCs for the first time this year with Platinum and apparently I'm doing something incorrectly when trying to redeem them.

This morning I called the Medallion desk and asked to have them apply one of my RUCs on my flight from ATL->PHX (27th on upgrade list) about an hour and a half before my flight. I was told to re-check in and I'd be at the top of the Upgrade list. I get to my gate and I'm not even on the upgrade list. Was wondering if it got coded wrong or something?

Gate agent was trying to tell me they do it differently this year so I don't know if he was confused or I don't understand how RUCs work?