When you "turn off" the "powering" receiver, it will still be powering the LNB.
On the H21, nothing "apparent" happens when the "powering" receiver either changes channels or turns off.
For the non-powering receiver, I'm not noticing any missing channels. What would I be looking for on the various transponders?
"The other one" should have problems with either the odd or even tps on the 101 SAT.
If it doesn't, then its working, and go pull the power cord on the other receiver and recheck the tps on 101.