While messing around as a new channels user I set up a manual advanced pass using title equals DW News and time contains 7:00 a.m. on the DW channel (I did this from the admin settings DVR passes page). I then set it for keep one recording, but it doesn't delete the old recording when a new one records.
If I setup the pass using the series ID and time contains 7:00 a.m. (i.e I create the pass from the guide normally and then add the time constraint instead of doing a manual advanced pass) it works correctly.