I can't imagine a ball ever accelerating to any position after it has been hit. It is at it maximum speed right after being struck. Wind resistance will cause it wo decelerate. So I can only explain this as you look at the ball "seeming" to be doing this, in reality it is not. But good to hear you hitting it better!

The left should turn back behind the ball is a crutial element that gains you great power and when combined with the flexability of keeping your hips and torso as still as possible in the takaway gains torque.