Another thing I just noticed ( not to be picky) is that you would benefit from forcing your heels down a little more, they aren't nessicarly pointing upwards but they aren't down.
Instead of forcing them down, allow your calf to stretch down and your weight to move into your heels. Be sure to relax your ankles though, don't "lock" them up or you will just be forcing them down. You have to trust your foot in the stirrup and let your ankles absorb the shock. I bet if you did this it would help with you over-jumping, as you would be more anchored to your saddle and less likely be pushing out of the saddle with your toes.
Every great dream begins with a dreamer. Always remember, you have within you the strength, the patience, and the passion to reach for the stars to change the world. ~Harriet Tubman