I think the second pitch is getting closer. I think the elbow needs to lead all the way to the hip. The hand will not start to rotate until then. Compare your video to Scarborough's Power Drive Commercial.
One thing I like to focus on is being loose and not trying to throw the ball. Key words are staying loose or limp like a whip. A whip needs no muscle along any of its eight feet to create a supersonic boom at it's tip. The pitching arm really only need the shoulder muscles to rotate the arm, and the muscles to hold on to the ball until it releases. A good pitcher converts all of the energy from her leg drive, along with a good circle, into the whip that's timed with the foot plant.
I think this is good advise.