The advice we give in our strategy miniseries is sound and it's supported by what the pros are doing. There are several factors at play in these videos that explain why the pros recover to where they do from shot to shot.
In this first clip Rafa hits a backhand cross court and recovers a few steps to the right of the T. Murray then rips a forehand DTL for a winner. That's an EXTREMELY low-percentage shot and Rafa was right to give that part of the court away to cover the safer CC reply.
http://www.youtube.com/watch?v=AG8jdpmCaVE#t=8s
In this next point, Murray hits a service return that is sorta CC but he still recovers to the middle. Why? Because his return is way less potent than his normal groundstrokes. His ability to anticipate the direction Rafa is going to hit is significantly diminished as a result. Rafa elects to go inside-out w/his forehand and recovers several steps to the left of the T (from our perspective). Murray uncorks another DTL shot to win the point. Again, a low-percentage play.
http://www.youtube.com/watch?v=AG8jdpmCaVE#t=37s
In this point, Murray's first backhand is DTL and he recovers to the T (vs several steps to the right of the T). He's probably anticipating that Rafa goes back DTL (which he does) given the match up -- Rafa is trying to work the ball over to his forehand side. Murray's next BH is ripped CC. Now he recovers a few steps to the left of the T, awaiting a short ball in the middle of the court (which he gets). He leaves DTL completely uncovered.
http://www.youtube.com/watch?v=AG8jdpmCaVE#t=53s
Finally, we need to consider the fact that when a pro goes DTL they often won't get to the proper recovery position (they have further to go than if they had gone CC) -- they might end up in the middle of the court. Why does this happen? Because of the speed of the pro game. They simply don't have time to move to the correct position. They need to be in their split step when their opponent is making contact w/the tennis ball and often that happens before they reach ideal positioning.
ASIDE: This is why hitting DTL is a low-percentage play. Not only do you have less leverage on outside groundstrokes but also you'll often be a little bit out of position for your opponent's reply.
If you watched our strategy miniseries you've probably realized from these videos / discussion that pros position themselves where they do for a number of reasons -- Directionals, "vanilla" court positioning, SWOT, DNO, etc. But at the rec level it's VERY HARD to go wrong by adhering to the simply concept that you need to be at one of three positioning points during a rally.