I kind of agree on mono. Most ceiling speakers aren't wide dispersion. If they are placed any kind of decent distance apart you can lose a lot of the sound in some stereo tracks or it just sounds off because you aren't hearing it all. Ceiling speakers tend to be pretty directional and beam sound straight down and not very wide so this further compounds the problem. Some models with wide array tweeters can help eliminate the issue and let you run stereo but really in this application mono is gonna be good enough. No ones ever gonna be like man this $hit is in mono not stereo but they will notice if its in stereo and sound that should be there is missing.