With the early backward break you do not get a bouncing effect at the top. From the time the hands are hip high only the arms, actuated by the shoulders, are moving the club. The club itself is not moving fast as it reaches the limit of the back swing, and there is a noticeable but not violent pull on the hands and wrists when it gets there.
Hence there is no rebound. The club starts down solely in response to the shoulder and hip action—and we are off to a late hit instead of an early one.
Since the late hit is the true manifestation of good timing, you have, right there, one reason the early backward break promotes good timing. The fact that there is no rebounding from the top, and no hurried effort then to get the club head to the ball, is also why this system makes it easier to establish a good, even rhythm.
But, you will say, the pros have no trouble with the late break and this rebounding of the club head. No, they don’t, because they subconsciously time their movements with it and also because they “tame” the club head by keeping a tight grip at the top. This grip is tight enough so that the club never gets away from them. But for the average player the timing is much more difficult.
The feeling that you have to move the body to get the club down to the ball, has its origin in the fact that for the last half of the backswing you are moving the club largely with your body and shoulders.
You are not moving it by breaking your wrists. So, since you have brought the club back with your body and shoulders, the natural thing to do is simply to leave them in command and start the downswing with them. This is exactly what should be done—the hips sliding laterally, and turning and rocking the shoulders to bring the club down.
The wrists leading at impact with no temptation to pronate or supinate are accounted for largely by the position the early break puts the hands and wrists into, aided by the fact that the body is swinging the club during a large segment of the downswing. With the perfect late hit, when the club catches up with the hands at the last possible moment, the hands will always be slightly in front at impact. The club has caught up enough to strike a straight, solid blow, but it doesn’t get exactly even with the hands until slightly after the ball is hit.
This will vary among the top pros, but pictures of many of them, taken at impact, show the left arm and the club in a curving line, not a straight line. Bill Casper and Wes Ellis are two examples.
The fact that a solid contact is produced on the centre of the club face is, really, the cumulative effect of many of the movements which have preceded it. Whenever the hit is late and from the inside the contact is much more likely to be accurate than if we hit too soon and/or from the outside.