I found it hard to read that article with all those animated gifs. Those things need a pause button.

Yes. I would guess that 95% of the time there is a fly ball with a runner on third it is a very easy decision. Most of the time the ball is hit deep enough that Billy Butler can walk home, or shallow enough that even the fastest runner isn't going to try. All those easy scores push the success rate upward. The coach would have to be sending a lot of runners with the chance of scoring is well below %73 to end up with a success rate of 73%.

I did a little research into where balls and strikes are actually called: http://902a.com/baseball-prospectus-idol-entry/. Basically, there an area about 7 inches wide all the way around the strike zone where you can't be sure what umpire is going to call.