Ludlow Slim-fit unstructured suit jacket in English wool-cotton

I ordered this suit jacket as a final sale item as it was just too good a deal to pass up, thinking that slim fit would just mean less boxy in the torso. Boy was I wrong. The jacket is actually a full size down in the shoulders, which really surprised me. The sleeves and jacket length fit true to a 40L which is great, and the torso was nicely slimmed down which is to be expected, however it is my understanding that slim fit shouldn't mean the shoulders are taken in too! This 40L fits like a 38 in the shoulders and is unwearable for me. I messaged with J Crew to try to exchange for a 42 (I've never had to size up from a 40 with J Crew suiting in my life) and of course they couldn't help as it was final sale even despite me explaining that I thought their sizing is off on this item. Don't buy this jacket unless it is not final sale. If you do buy it, size up as slim fit apparently means its a size down in the shoulders in addition to the torso.