You’re not “managing” SB8200 with the SURFboard Cental app.  The app guides you with modem activation and help register the SB8200 with ARRIS.  You can use the SURFboard Central app only for the SBG10, but you have to be at the location to manage the SBG10 with the app.  

If you’re looking to do remote management, the SURFboard Central does not support it. 

However, you can remote manage mAX routers with SURFboard Central app.  

Sorry for the ignorance.  If I am on the network that has the SBG10, should I be able to see it in the SURFboard Central App.  All I see when I open it is the SB8200 from the other home.

The App doesn’t pick up the device automatically and I don’t think the app will allow you to add two modem devices to an account. You’ll have to remove the SB8200 from the app first then add the SBG10 to the App.