Hi Bill,
There are two types of fitting types.
Type 1 is easy. Their swing is their swing. If you hand them flatter
clubs, the lie mark is at the toe. If you hand them upright
clubs, the mark is at the heel. Bend accordingly.
Type 2 is harder. The mark is in the middle, regardless of length or lie. These people change their swing to fit the club.
Bill, it seems as though you're type 2 - fitting your swing to the club. My guess is that when you stand a little more bent over, you swing better. (It sounds like your coach agrees).
One of the things we talk about in club fitting is that static fitting is a starting point. Yes, charts will suggest standard, or a 1,2, or 3 degree change. But hitting
clubs off a lie board changes everything. (By the way, when you hit off a lie board, were you hitting something, or just swinging?)
I'm glad to hear you're hitting the ball well!