You look at the entire package. SOS is so deceiving; my take would be to look at contribution to the success of the team. In the example that you gave, Kahn's efforts have helped yield higher results, hence a greater contribution to his team.
You can look at Evan Jones from Trinity; vitually the same numbers as Kahn, again his team is moving on. I would look at contribution to the success of the team more than SOS. SOS has been discussed all over this board and most would conceed that geography can be a major factor in a teams SOS.
I wouldn't like to strech pitching to cover SOS; it has been my observation that good teams see the best pitching in their region. You will see some variances in performance from game to game, you are looking at a seasons worth of success. In my book, unless one is playing in just an awful conference, good players see the full gamit of pitchers.