In case it hasn't been obvious to those of you who have read some of my other posts, and for a bit of background for those of you unfamiliar with these musings, I HATE adjustable hosels. I want to state up front that this post is not an explanation of adjustable heads -- it's a question.
It's not that I hate the concept, and I may even enjoy playing around with them myself, but I think they are a piece of marketing fluff that creates more problems than they are worth for the average golfer. Most of these problems come from a lack of understanding of how these work and the effects that come as a result of these adjustments -- they adjust aspects of the club that most people do not appreciate or understand.
Here is a post from another thread. This comment was made in response to a criticism leveled at adjustable lofts: Yea it's stupid really, You only actually increase/decrease the loft if you square the face at impact as I understand it. So if you close the face to increase loft you must then hit the ball with the face square, which is actually open from where you started. Reverse for decreasing loft. Just give me a driver with more/less loft and be done with it.
I think this post actually illustrates more understanding of these hosels than most people have. It at least acknowledges that face angle (FA) is affected when you change the loft with one of these adapters. IN FACT, when you "adjust loft," you aren't really adjusting loft -- you are adjusting face angle ONLY. You cannot adjust the actual loft of the club head without a hammer and a vise (don't do that!).
And here's where the confusion comes in (and I include myself in this confusion). AS I UNDERSTAND IT, if you square the club at impact, the club has the loft stated on the bottom of the head. If you have adjusted the loft via the adapter and you come into impact with you hands in your "normal" hitting position, and the face will either be open (if you strengthened the loft, I believe) or closed (if you weakened the loft -- again, I believe). The only way that you could have the loft changed and the FA square is to adjust where you hands are at impact (either ahead or behind the ball), which you don't want to do.
Again, this is just my understanding, and I would really like to get confirmation from someone who really knows about these adapters and their effects (Scott?).