It can use the same SSID, but in reality, it's still two separate connections and running the same SSID won't allow you to pick and chose which one you want to connect to. For the device closest to the extender, it should automatically pick up the stronger signal, but if you're connected on your phone and move about your place, your phone could continue to maintain the weaker SSID. I don't know if your router and/extender has the ability to set minimum RSSI to release the connection so your device can connect to the stronger signal. However, it shouldn't be a problem for your Apex because it's stationary.