My existing set has progressive offset. Love it. It helps elevate the lower lofts. I think it is a good design feature for SL. Cobra also uses progressive offsets. Don't overthink the one ball position concept. A couple of millimeters means nothing. Not to mention the adjustments you make for an uneven lie, to hit the ball a little higher or lower, etc.
That being said, the overall offsets of the I-Wins are pretty big, and so are the bounces.