Edurata Polka Dot Long Sleeve Silk Organza Maxi Shirtdress

I own probably a dozen or more pieces by this brand, but they range in size. I just don't understand the sizing. I honestly never know what size to purchase. This dress did not fit because the slip worn beneath the sheer dress was way too small in the hips. The outer garment fit well, however. The under slip should have been sewn on the bias like a slip dress to conform to the body.