Thank you for your reply. Since you brought it to my attention, I have updated my drawing to better describe the situation ( I did forget about the Separator that came with the 622). So here is the updated drawing:
View attachment 32044
So, I am interested in your idea of using the #2 tuner on the 622 to do away with the 4900. As the house is pre-wired with only one RG-6 going to each room from a demarc point located near the DP-34 in the drawing, how do I get the signal feed to the upstairs TV where the 4900 currently is?
It appears that the required solution is to ditch the DP-34 and go buy a DPP-44 in order to take advantage of the DPP properties with only using one cable. I don't understand the "power insertion" part of the DPP-44; seems that the power needs to be inserted on the interior of the house, but in-line on which piece of equipment, or does it matter?
When I got the DPP Twin for the 500 dish, my plan was to have a the option of using the LNB In port, so that is why I didn't get the DP Twin. If I ditch the DP-34 in favor of the DPP-44, that should correct my issue that you spoke of with my current configuration idea.
My apologies for the long read, and I thank all of you in advance for your input.