You could add front tops or heights, but you wouldn’t have any dimensionality. Part of Atmos is that it uses the overhead speakers with the ear level speakers to place sounds(objects) in and around the room. When they’re all on the same plane, it doesn’t really work. You will have the sounds that are supposed to be overhead, overhead. But the object placement and immersion won’t be effective. If it really matters, I’d have a meeting with the war department and see if there’s a compromise to be had. I’m fortunate to have 7.3.4 in my living room, and while it has its compromises, it’s not because my wife simply said so. Everyone’s WAF is different though, so good luck.