from game manual :
During the course of the game, your coach will make adjustments as a result of how the game is going. If you are making a lot of inside shots, he will tell you to take more inside shots. If the opponent is making a lot of inside shots, he will tell your defenders to double-team in the post more often. However, any time that the coach makes a change away from the tactics you started out with, it will be a less effective than if you had simply chosen to double-team the post all along (i.e., you will find that it is easier for your coach to tell the defenders to focus even harder than they already are on inside defense if you are already playing a 2-3 zone). The closer your submitted tactics are to the optimal choice, the better, especially because the coach is only able to make limited adjustments once the game has started.
Its all couch fault. :))