I have had to replace both Sphere lighting receiver modules on my 2013 Jayco Sterling ($130 each) and have reprogrammed the individual wall switches without too much problem using the provided instructions . I am a little confused however in to how to setup the Master OFF switches? Anybody out there had to do it?

Jeez.
$136 EACH light receiver. 5 x lights.

Think I'd be doing the wiring trick myself.

Contact dealer who sold you the recievers.
They should help you methink's, (Caravans Plus do)

That's an awful exxy way to wire anything. Specially if nor reliable.
Another Jayco con trick hey.

I had that problem when I discovered that my bedside Master OFF switch had not turned off the outside lights - discovered that at 10am the next morning after surfacing and exiting the caravan! The lights had obviously been burning through battery amps for around 12 hours. Investigation showed that only the doorway Master OFF turned off ALL the caravan's lights, both interior and exterior. Discovered also that the other bedside Master OFF also only the interior lights. So I did something about it. It wasn't hard.

As I was on my own, I positioned a mirror so that I could view the LEDs on both of my remote receivers as I pushed the doorway Master OFF. I noted that all 12 of the little green channel LEDs lit up. So I then re-positioned the mirror and moved to the bedside and pressed one of the bedside Master OFF switches. In the mirror, I noted that 2 of the green LEDs didn't illuminate. Those were the 2 receiver channels allocated to the outside wall and awning strip lights. A quick read of the one-page user manual revealed the method on how to program the switches.

1) Press the programming switch on the receiver module corresponding to the channel you wish to program for 5 seconds , until the LED on the corresponding channel flashes green,
release the programming switch, the corresponding channel is now in learning mode.
2) Press the remote switch button (i.e. the Master OFF switch) that you wish to program to the receiver.
3) When the receiver module receives the wireless switch signal, the LED corresponding to the programmed channel will flash orange once. The wireless switch is now programmed to the corresponding channel.
4) repeat 1) to 3) for each of the lights you wish to control from that Master OFF switch.

Contacted Jayco Cairns and the service manager talked me through it. The wireless lighting is a great idea and the way of the future but expensive when it fails. Thanks for the help.