Another issue is that you're closer to the diffuser and therefore the diffusion isn't as diffuse, if that makes sense. For instance, my room has about a 7'8" ceiling, which is a full 4-6 feet shorter than Tony's room. If you think of diffusion as a cone emanating from a single point, Tony is going to be at a location much farther from that point, meaning that the sound will be more diffuse. For me, I'll be much closer to that point, meaning that the diffusion will be not as effective or ineffective.
Or is the cone so big it doesn't matter?