i agree with this especially the last comment. when a well trained dog gets to the level that it's doing what you want i think you have cracked it. at this point you have managed harness all the best qualities of the dog ,instinct, prey drive, breeding, fitness etc and take it that little step further. its the difference between a good dog and a great dog 
i've always stood by that poor training can ruin a good dog but proper training can make a good dog great