In other words, the shorter the playlist, the higher they rank? I thought so.
You'd have a good point if those three stations were classic hits, but they aren't. You'd expect small playlists from a CHR and a HOT AC and besides, in that area, currents would most likely top the rankings anyways due to popularity and population.
What the average size of a CHR playlist? About 30? HOT AC, less than 100?
Now, if any those stations were classic hits, then yes in your case, you'd expect a higher ranking than #4 with a smaller playlist of classics, but that's not the case there.