They look clearly pointing directly vertically to the floor. Perhaps they are in a "rest" position, waiting for further optimisation. Or perhaps they have a very wide dispersion sound. Or Steven does not like a very aggressive sound stage from above.
Just google for "Atmos studio" pictures and you will see many Atmos heights/tops totally angled to the MLP.
Would that affect how Steven make the amount of sound content from above, in his Atmos mixes?
In my room I have Atmos speakers "in ceiling" "stagnant", but with orientable tweeter that I angle 45º to my head. I ended changing the Top Front Left tweeter to other direction to get more even Helicopter demo sound turning around. The room shape and reflections on the walls may change your perceived coming sound direction. But if you point a monitor shelf speaker exactly 45º direct to your head, I assume you will get full speaker performance and sound with minimum reflections on the walls.