There are only three things that matter for evaluating a team on a drive, where did you start, how many points did you score and what position did you give the ball back to your defense/special teams. Plays taken to achieve results and time elapsed off of the clock can be valuable in certain situations, but in general those three data points are the key. If we can effectively measure each play in how it contributes to those three key factors at once, why break it up into two pieces and why make it black and white?