Dave, You can do whatever you wish on this subject but I think that a stepped baffle isn't necessary. My reply was more directed toward a focused baffle than what you are suggesting. But I'm pointing out that it isn't necessary to step the baffle and in fact might lead to lower sound quality as you distrub the wavefront. I'm not buying the sound smearing issue that you raised as I believe that you don't have it in the vertical axis near field as I wrote in my earlier reply.
Jim