That’s a great breakdown.That mostly depends on your room size and speaker placement. If you have a moderate sized room and your Top Front/Top Rear speakers are positioned at close to recommended angles (45 degrees before and behind your seats), the need for Top Middle speakers between them is minimized. Those speakers will probably do a fine job of imaging sounds between them right above your head.
But if you have a very large room and/or your height speakers are in compromised locations (e.g. Front Heights and Rear Heights far away from each other), you may not get much imaging. That's when an extra pair of Top Middle speakers between them is most helpful.
But is it an accurate observation, that in a 6 (Dolby atmos) height speaker setup, most of the activity is concentrated in the middles? I’m really getting some mixed feedback. Hope you could shed some light on this. Thanks for being such an awesome resource on this board. Cheers!!