Using the methodology described in this thread, I found BE award travel for two in January LAX-NRT-BKK on DL and BKK-ICN-LAX on KE at mid and low award levels on DL.dumb. I live in LAS and was unable to get DL.dumb to find these awards when adding LAS to the reservation. I placed the LAX flights on hold and then called the DL Platinum desk and asked them to add LAS-LAX-LAS on to my award reservation. The reservation agent told me it cost 60,000 miles additional for each person.

Is it possible to add a LAS to my reservations without using additional miles??