I just want to confirm that my extender is working fine. 

I set my extender up using the wps method.

All 4 lights are blue.

When extender is off - Using my phone WIFI, I do not see either of my 2 home networks (from my router/modem 2.4 & 5 ghz) or they are very faint.

When the extender is on - I see both networks at 75% or better strength.

To me this tell me my extender is working fine BUT...

A friend recently told me that I would need to login to an extender version of my network to be actually using the extender function.

I never see 4 WIFI networks when scanning for networks on my phone - no matter were I am in the home.

I just login to one of the two router/modem 2.4 & 5 ghz networks once.

Is it possible that my WiFi is automatically transferring from the modem to the extender without having to login to the extender manually.

i.e the network name and passwords are transitioning seamlessly using my router/modem 2.4 & 5 ghz networks and passwords?

I hope I have explained my concerns. I just want to confirm that my extender is working fine and that what my friend said is not always true, depending on how my setup has been achieved.