Window?

I agree with star_rider.....let it be if it sits COMPLETELY on the sill. Just make sure ALL of the edges are on the same level...i.e...are all on the sill. Window sills have a LOT of structural base so i wouldn't worry about that....just make sure it sits level!
 
It sits very level. More so than where I had it before, even. Thanks for your input.

Also, that is a very interesting avatar you have! I kind of want to pet it...
I mean the bird-dog thing. Not the avatar haha.
 
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