I bought 2 pairs of levis, same model and size, made in the same country (Mexico), the only difference was the color, one on black and one on medium-stonewash, my surprise was that they did not have the same measurements at all. The black one fitted perfectly on waist and on legs, but the m-stonewash was just wider in waist and short on legs... I had to do some stitching work on them in order to make them fit as the black one, for the short problem I had to live with that ;). What I want to express is that it was a failure of their Quality Control, they should be exactly the same, but they are not.

PD: One more difference was that the black one was also "waterless" made. At least it is what was written on the cartoon label.