I think a solid four channel amp might be a good addition for people moving to Atmos. If I ever get the chance to add it, that's what I'll need and I think anyone already running a 5.x or 7.x would only need the extra for the Atmos overhead channels. I haven't really looked but it seems like it would be an odd number prior to the advent of the object processing formats. I suppose one could just use a five channel amp and have an installed spare, but a four channel could be marketed as an Atmos Amp or something. They could maybe even include accessories to bi-amp the outputs in pairs for folks that want strong two channel performance instead. That would allow it to serve two comparatively smaller markets with one product.