It has been awhile since I updated this thread. Unfortunately, there is even more bad news, this time regarding my Hopper Duo. I activated my Hopper Duo today, and the Model listed on the Diagnostics screen changed to "Hopper Duo D." I was immediately filled with dread, thinking "Uh-oh, here we go again!" Sure enough, when I checked DVR functionality (Pause, skip back, skip forward, rewind, fast forward) I am now having the same problem with the Hopper Duo that I previously had with all of my Wally receivers. The function does not work, with a pop-up in the lower-right corner of the screen saying that function is "unavailable for this program." This happens on both Live TV and existing DVR recordings. Existing recordings will still play (thank goodness) but there is no way to do "trick play" while the Hopper Duo is activated. Just like on my first Wally (before I tried switching to a different Wally) full DVR functionality works on those same recordings while the Hopper Duo is deactivated. This is happening with Hopper Duo software version U648.
The other weird thing is that when I activate the Hopper Duo, the My Programming section on mydish does not list any DVR fee. It only adds the $14 fee for having my ViP222k on the same account. So, it is treating the Hopper Duo as the primary receiver, but with no DVR fee. At least Dish's billing system seems to already be aware that DVR functionality will not work properly with this account, but that still does not explain why it is not working.