@Franz47 Those units are designed for both wall and ceiling mount.  I would not change it's mounting position as you would likely lose some signal quality with the meshed unit, and you won't likely gain much if anything in indoor coverage.   Rest assured, RF is like light, sure it travels in straight lines, but it really bounces and reflects off a lot of things!

My understanding is the peak radiation point is directly in front of the front face of those indoor 'pancake' APs, so it's best to leave that generally aimed at your outdoor unit.  The hard surfaces in the room (unless the room is absolutely huge) will take care of filling any weaker coverage areas immediately to the sides of the AP.