The Surround Back speakers are meant to be at ear level with the Front, Center and Surround Speakers. Again, when playing Dolby Atmos or DTS:X tracks or when using the Dolby Surround or DTS Neural:X up mixers, the A4A cannot use both the Front Presence speakers and the Surround Back Speakers at the same time.
Just to clarify, are you talking about Surround or Surround Back speakers? There are no Surround Back speakers in the pics I posted from the manual. Those are the Surround Speakers. If you cannot place the Surround Speakers at ear level, things become even more complicated for you. You would then leave Front Presence and Surround Back Speakers out and configure the receiver for 5.1 and place the Surround Speakers in the ceiling just behind the listening position. This is not an entirely unknown practice as some simply cannot accommodate Surround Speakers at ear level in their room.