I am not quite as surprised by the results although in the perfect model doubling the measurement on the rectangle would cause problems. However what we don't know is the materials in the room,whether your measuring a blank room, ect. The one question concerning what's above the ceiling is the right one. Acoustical applications can make all the difference in the world. In my app. I paid a lot of attention to what went behind the wall,ceiling,and floor. Despite things I couldn't change about an existing configuration the result with regard to resonance and other issues was very satisfying.