If you want cool effects in a war movie of a plane flying by overhead, then awesome.

But in most television and movie scenes, the sound is coming from a circle around you on the ground.

Putting another 2 (or 4) speakers on the ceiling isn't usually going to make much of a difference. It's truly just diminishing returns.

For the war or action movies where it does, my advice is just to go see it in the theater.