Not to add to your confusion but it is possible to show up as "CLOSED" and still be available to use at least according to two different DM CSRs. I have a RUC that I tried to use on the LAX-BOS nonstop in late November but failed as the flight frequently sells out and did. I knew it would likely sell out but used it to jump to the top of the upgrade list in the event of a no-show or late cancellation. I was not upgraded but the next day I checked Delta.com and the RUC was marked as "CLOSED". So I called up twice and was told that while it showed as "CLOSED" to me that there were two data points available to them and one showed it was not used. I was told there is a glitch in the system but not to be concerned as I could call up an apply the RUC for a future flight. I haven't tried as yet as all my flights the last 3 weeks have been 2 hours or less and not worth using a RUC.