If you click the last bar it will tell you about the last game, and the current ratings of both players at the time the game ended. There is a bar for every game, so no unaccounted for games.
If I understand you correctly you wopuld wish the heigth of the last bar to reflect the rating after the game has been rated. This would be possible and you can forawrd that Idea in Site Ideas, but I can't see an improvement there.