The SWiM is fully loaded, with the max 8 tuners. Getting the R16 in dual tuner mode will require a SWiM-16. [might not be a bad idea]
When the tech added a splitter for the PI, and signal issues started, it must have been due to the PI not powering the SWiMLNB well enough.
The common PI is a 21 volt, but the other PI is 29 volt and might be worth a try.
Without being there to sort through everything it's hard to sort out this.
Troubleshooting the playback issues to between "x & y" would help, and this might take moving/swapping receivers around.
I doubt anyone wants to go into the attic and check if the cables are tight and the three unused ports on the splitter have terminations.
"Normally" DECA isn't bothered by open ports, but SAT signals are.
I don't want the R16 in dual. I never use it except for the second football game on Sundays.
I checked the PI and it is 21 so I can throw the 29 volt one at them as an idea.
They did go through the attic at least once (day 1 for sure when he changed out the MSPLIT8R0-01 (he left the old one so I am looking at it) and changed the LNB on the dish. He said all connections were tight.
I am not sure what else at this point either. Not to mention the frustration factor!