Why don't you get runs made before the ball reaches the boundary rope, like you do when there are overthrows?

This is a very interesting question. However, unfortunately this point has not been taken care of in the rules of cricket. According to rules of cricket once the batsman hits the and if the ball crosses the boundary, 4 runs is awarded to the batsman and the runs made by him by running before the ball crosses over the boundary is not added to his account, whereas the runs resulted due to overthrows are added to the runs made by him by runningbetween the wickets..