Agree, I definitely think there is some shenanigans happening behind the scenes, hehe.
I used to think it was because the player was ranked higher than me, therefore had the advantage. But recently, I played someone who was ranked lower, but that person ad the advantage, so there goes that theory.
I have another theory which I need to test. Perhaps the top or bottom position dictates the advantage.
I think its completely random but I am interested in your theory.