Trouble adding another Orbi Satellite to existing Orbi setup

The Model field won't let me enter the actual item I'm talking about, which is the RBS50 (Orbi satellite)

A couple months ago I set up an Orbi system in our house (one router, connected to an existing Netgear modem/router - with the wireless radio disabled - and two Orbi satellites). I had no issues setting everything up and getting the satellites to sync with the Orbi router; I didn't even have to push the "sync" buttons, it connected on its own.

Side note:
The performance has been good the closer we are to the router and satellites, of course, but I did find something odd that I didn't expect. A bit disappointing too. The wireless strength was actually *weaker* after the Orbis were put into place than the strength we'd had with just the Netgear modem/router when its radio was turned on. Why would that be? Did the satellites somehow not really sync, despite the light code indications that they did? I don't understand this. I figured the strength would be much better than before and that I wouldn't even need any additional equipment. 

Anyway, because of this issue, I've since purchased a third satellite to put in a different place in the house, but when I plug it in, and it starts up, it just stays lit with a white light. It never syncs on its own. Now, I know I'm supposed to press the "sync" button on the satellite and then the router but my fear of doing that is this: will is somehow disrupt the other existing connections and I'll have to manually re-sync everything again afterwards?