Points awarded for the win

mayday_bbb

Why did my opponent get 20 points for a win in this game lichess.org/nJ2LtU5VtH09 , and I never got more than 8 points for the win (even when I was playing against better rated opponents)?

beautiful_berries

edited

http://www.glicko.net/glicko/glicko2.pdf. I hope this clears things up