Awesome, but why?

So I read a bunch of advice on the forum, and weakened my grip and dropped my back shoulder a bit. Not only did this cure my hook, but it also fixed my swing plane. Oddly, I had a vertical swing and these changes helped flatten it out. Any idea's on why? I love the results, but would like to understand it.

With no video, this is just a shot in the dark. Many people swing with their natural plane coming through their shoulder line. If your right should is slightly lower, it may give you a slightly flatter plane. But flattening your plane is the cure for a slice not a hook. So, who knows?

A strong grip may promote pulls, a weak grip may promote pushes. That you hit less left with a weaker grip is only logical.

Both of these make sense. I think maybe lowering the shoulder was the key to getting me back on plane, but my grip was SO strong that I could never fully get there with just that because I couldn't really hinge my wrist. The result at the range is a consistant baby draw, with a miss being a slight push. Can't wait to get on the course tomorrow, really feel like this is the move that can turn my HCP in the right direction.

For a long time I set up with open shoulders. This gave me a pretty nasty little inside out swing. If you hooked the ball perhaps your shoulders were closed at address and perhaps dropping the back shoulder squared them for you.