For some reason the washed leather feel really snug when you buy your normal CP size. I am sized perfectly at a 41 in achille lows and I remember the washed browns feeling really tight. I would say a good rule for the washed is if you're pushing your normal CP size in achilles, then go ahead and size up in washed. If you have a little bit of room in your achilles and aren't maxing out the length (edit; and width), stick with your normal size for washed. I think it is because the tongue is thicker than on the traditionals. In looking at the shoe it is important to the design, but a real pain in the ass when you've owned a lot of CP's and they throw that curve ball with no warning in the description. Maybe try swapping out the rounded laces for the normal flat laces if you have an extra set to reduce a smidget of extra pressure pushing down on the tongue and thus your foot. That may be a long shot though. Good luck.
I find 100% of the above to be spot-on advice, from first-hand experience.