I am playing someone who is rated 180 points below me. If he wins, he gets 12 points; if I win, I get 4 points. So over 10 games, I would need to win 8 games to get 32 points and make a net profit of 8 points. That is just not going to happen against a reasonably skilled player; there is just too much luck in backgammon games. It means that I am virtually forced to play opponents at my current rating and so my choice of opponents is very resricted.
A much more sensible approach would be to have 7/9 range for a difference of 150 rating points and 6/10 difference for all the rest.