Looking at the attachment, and assuming that the bird at 121 is EchoStar 5, I would say the channels listed are remaining on 121, just moving to a different transponder for some reason.
Example: PHNIX, Channel 680, will stay on 121, but move from Transponder 520 to 529.
Based on Transponder 520 means EchoStar 5, Transponder 20.
But I haven't had my medication yet.