grenv: Your observation seems to be correct as long as the opponent is within 400 points of your rating. If the difference is greater than 400 points, then you will be penalized heavily for losing while gaining very little if you win. This is why I try to limit my opponents to those within 400 points of my rating.
(hide) If you want to play a game with an opponent of a similar level, you can define a required BKR range for a new game invitation. Then nobody with a BKR outside this range will be able to see/accept it. (Katechka) (show all tips)