pentejr: Your opponent probably had more completed games than you. Until you accumulate a certain number of completed games, your ratings adjustment after each game is modified (increased) by a factor that declines as you gain experience. Since you have completed only 42 games of hypergammon, your ratings adjustment is greater than it would be if you had already achieved the level of experience at which the extra factor ceases to apply. Your opponent was probably closer to that level than you, and therefore had a smaller adjustment.