I would handle this via email or twitter. UP fares earn 150% per the earning chart. Many phone agents don't realize that and just look at the fare basis. An email rep could look into it a bit more. Good luck!
Just another example of Delta IT not knowing its a-- from it's elbow.... poor execution. Dummy bookings still show -UP fares earning 150% MQM and RDM, so take it to twitter.
Hopefully enough clamoring from those paying attention will lead to a fix, although I doubt it. I imagine some MBA has demonstrated the cost savings associated with this "glitch" and will simply leave it in place.