Win bonus is useless I guess...
On my GF's team, because I knew she couldn't qualify for the finals in CL, I turned off the win bonus...
2nd last game, 1st half was losing 2-0...
Then I changed the formation and... wtf won 2-3!
Playing against the first of the group and in an away match!

Today I played agaist a friend, who before the match did a friendly agaist me so he could counter my formation..I won the friendly 4-2..
But in the league, lost 3-2, obviously he changed his formation since the friendly... My win bonus was set to 600K.. Lost the game and the
league lead.

So win bonus is useless.. Countering formations and strategies is what it matters...