Leading wrist and the club is at a position of less than 180deg .Players with this wrist setup (Palmar Flexion) will require additional loft, as setup of the wrist will decrease loft.Some Tour player,like Phil incoporate such setup, require up to 7 deg of loft.
Leading wrist and club in-line at straight 180 deg. It is how most of the putter is setup to be. Therefore, reflecting the actual loft setup.
Leading wrist and club larger than 180 deg. Players with this wrist setup (Dorsi Flexion ) will require less loft,
as the setup of the wrist will add loft.
Tour Players, like Zach Johnson, have this kind of setup will require less loft, Zach plays with less than 1 deg of loft..