Indeed I am using shoe trees. Mine are also 4-5 years old vs you 6 months. The creases don't bother me so much as the stitching just looks uglier when it's all splayed out like on mine as opposed to a nice clean arch on others'. I'm wondering if I should be taking a 6.5 narrow as opposed to a 6 regular.
I wish my feet would keep my 403s looking pretty in the toe box like you guys. Mine get all distorted along the stitching... I guess due to foot shape/flat feet. Anyone else have this problem? I suspect it isn't as bad with the 405s and other less stretchy leather models.