In the scenario you list, in theory, if you increase the loft to 11 deg. and the face sits closed 2 deg., if squared at impact the effective loft is 13 deg. The question is when the head is adjusted to 11 deg., what is the face angle when measured? Loft should always measured with the head sitting square. I think a lot of companies with adjustable hosels don’t do that. In fact, I know they don’t. Anyway, if it’s truly 11 deg. when it’s 2 deg. closed, the loft at impact assuming a square face would be 13 deg. I know it seems like if the head is rotated back to square it would return to the 9 degree, but if considering the relationship between loft and face angle in the traditional since, it can’t be 9 deg. at impact. In my mind, which is a scary place, when a head is adjusted, it is adjusted in two planes. In the golf swing, starting closed and returning to square affects the club face in just one plane, or not in the same way. Also, some adjustable heads have two cogs and some don’t. Results are different depending on what system is employed.
If you’re after 11 degree loft at impact, the 10.5 deg. set at standard is going to give you a more predictable and closer effective loft to the 11 deg., at least in my opinion and in the scenario you laid out. Just a note here, adjustable drivers are great and give us a lot of flexibility, but you have to be careful relying solely on the charts that show how the adjustments will affect the loft, lie, face angle, etc. This is because of the inconsistency in how each manufacturer measures. We measure ours with the sole sitting on the ground and what the chart says delivers launch angles and spins that are consistent to what you should see in each position. Of course, it can be different for every player.
It’s a good question and a head scratcher for sure, but the opinion around here is consistent with the above. We could be wrong, but before I would admit it, I would want the heads your considering so we could measure them.