Divots occur for many reasons other than too big or small. In this case it could be arm and or shoulder pitch. Also, shoulders could be sloping and pitching forward which can create a divot. Will be worse if sizing down if that is the case. If those are the case, it's a problem handled at the pattern stage. Worth checking a size down and size up for the heck of it but posture may have more to do with it. I have to look at suit supply stuff. It looks very Tom Ford esque. So far, I've seen no rtw brand that can stack up to Tom ford so I'd love to see their product.