Annahouse blouse sizing help

Hello EGL, I have a question about the general sizing on Annahouse. I already own one of their blouses in size S which, according to their website, should not fit my bust at all. But it fits just fine (maybe a tad tight but the buttons don't gap). Now I'm looking to purchase a few other blouses from them but it would seem their sizes change from blouse to blouse, and I'm curious if anyone knows if their other blouses (specifically 016-1180 and 016-1312) are true to size, or just as stretchy as the one I have? If I choose a blouse that fits my bust I'm afraid it'll be too large around my waist but I'm way too impatient (and cheap) to custom order an item.