Newbie here (may have actually had an account here years ago but if so I forget the login for it), hopefully this is the right place for this question.

Does anyone here need to size up for outerwear?

I was checking out the Arcteryx Cerium hoodie yesterday, and going by their size charts I should take a medium. Im 185 lbs, 38-39" chest, 32-33 " waist and a medium fit fine with just a base layer on, but once I added thicker mid layer it was pretty constricting in the shoulder/upper back area so the sales person said I should go to a large which gives me the shoulder room but than is "blousy" in the front.

The same thing was essentially true for a few other brands as well. It seems these measurements are designed around rail thin people, and not guys who have a more developed upper back/shoulder/bicep area.