you are probably right. Just peaked at my neighbour's plan whose house is a copy paste of mine. It appears their design shows 4 in total. two top top bottom. Probably a better way and doable if everything will be rebuilt.I have to say, that's a big space to cover with just two speakers, even bookshelf speakers.
They installed passive speakers to be hooked up with Sonos amps. Some special setup specifically requested by them.

