Any point in using "front height" speakers for Atmos front configuration?

I just realized I could perch my old Polk TL2 speakers high on my windowsill and tuck my wires behind the curtains so they are totally unobtrusive in that setup. This is about 7.5' off the ground and 18" from the ceiling.

There is no way I'd install in-ceiling Atmos speakers in this room, but I'm wondering if I ran them these speakers from the top front outputs in the Denon X1300, would they have any beneficial function in Atmos mixes?

I know Atmos relies heavily on reflections from the ceiling, etc. And in this configuration the speakers would be pointing directly out into the room, about a 45º angle from the seating position.

http://i.imgur.com/aQaXw9n.jpg