the difference goes to the miners exactly for the fact wo don't want any change address! (you could have also send 20.8 instead so you wont sponsor the miners)
Ok that's the key element I was missing, that basically there are no change addresses (although if 0.1 is the minimum that means every anonymous payment you make will incur an additional cost of as much as $0.51 at present, presumably this lower bound will decrease in future).
BlockaFett: now's the time you do a little happy dance and write lots of bold text about how one of my conclusions was incorrect. You can even call it "BS" and say that I "don't understand anything" if it'll help you with your self-esteem problems:)