I'd still disable the swim8 and use a regular diplex to get the signal In instead of the swim8 over the air input myself. No need to run a 21 v power supply and add more heat or no reason and as Carl said you lose some signal that way.
But hey if it's all working perfect!!!!
What I gather is the the OP has 4 DVRs (one being a Genie) and is using DECA for two of them (on the SWM16) and using the SWM plus OTA on the other two. I wonder if dipexing "one side" of the SWM16 affects the "other side" that is using DECA