Sveta, they are the same size.
Suz and Talific, the size up was clearly too big in the shoulders. If a looser looking fit is desired, then I might as well stick with the one button blazer. The two actually fit almost exactly the same through the shoulders and back.
So I think what is making it appear too small when buttoned is not that it's actually tight but that the stance, even on the two button one, is too low. It's hitting completely below my bust, which makes the excess material at the bust pouf out in a weird way. The stance on the one button is also too low but it's so low that the bust doesn't pouf.
I'm not sure I ever want to wear it buttoned, but on the other hand I'm not sure I don't want the option to be able to do so...
Adelfa, glad you like the side view. I was actually unsure because the fronts are longer than the back (that is how it is designed) and the other one is longer in back which maybe seems more conventionally flattering to me.
CF, I agree the first one was better with jeans. But to be honest neither of them is exactly the look I wanted for the BF jeans anyway. I think for that I just need to get an inexpensive drapey blazer like Una's.