Using my router connected to an XB6 without bridge mode and everything works, is this okay?

Is it okay to use your own router connected to an XB6 Gateway and not be in bridge mode? I'm doing this and everything seems to be working great, we are actually running slightly above my plan on speed (which is nice) with 15 or so devices connected to the router (wired and wireless.) I do have wifi and the hotspot on the XB6 shut off. Are other folks doing this? Is there a downside? Related – I did go into bridge mode for a test and it seems to kill access to the XB6 configuration page at 10.0.0.1, is there way to fix that? It took a support call to get 10.0.0.1 access back and we had to go out of bridge mode to do it. (Weird.) Or should I not worry and is it okay to run like this? Any down sides to one router sitting behind an XB6 still in router mode?

(BTW - We backed into this set-up when we recently switched from an XB3 to and XB6 gateway and thought all of our old settings had transferred including bridge mode based on what the comcast support rep said during XB6 activation. Everything lit up and worked great across the network via my router. But checking 10.0.0.1 bridge mode was off.)