The thing about toast sizing is that it's not consistent - also many other brands, so you could go on blithely ordering 'your' size and quite often end up with something that just doesn't fit. I am fairly sure Toast doesn't mean for that coat to look odd on the shoulders.
I also don't really care too much what a brand wants something to look like on me - it's more about how I want it to look. Eg my favourite jumper ever is a very thick shetland style cashmere jumper from Gap - It's a size L tall and I'm neither large nor tall but it's perfect!
One thing I found interesting when I was trying to work out sizing for the plus J Uniqlo collab - watching some strange Youtube videos by Japanese women - they quite often bought very big sizes which changed the look of the clothes in a good way, and also bought men's pieces too - and thinking back over my life I've often also bought men's clothes! Did no-one else used to live in those wonderful huge lambswool jumpers from Marks and Spencer?
Anyway I have found the coat in a 10 at one of the outlet stores and am going to gamble on the fact that I'll have to pay to return it if it's no good. They're posting it to me today hopefully so will cross my fingers!