Used my last 2 of the year for a work trip for RDU - SJC and return.

Quick phone call and they were able to process without issue.

One thing to note, DL.com display tags were not correct. On the flight search screen it showed SEA - RDU had no RUC space but if you actually clicked on the link the pop-up showed it that it did (and confirmed and cleared when calling in).

Another good use of the RUCs