When serving, a team must have made several decisions before the ball is served . Of course, you would because in fact you are in greater control. When I coach the men's tennis team at Albertus Magnus College, I insist that the teams answer each of these questions before each point. Usually, I have the net person make the decisions for the server. However, the server can reject a particular proposal, if he believes it is too difficult or ill founded.
Most professional teams talk in between each point.
They usually have played their opponents before. Thus, they have probably decided a general game plan and backup plan before the match. During the match, arriving at the answers to the above questions is usually a fairly quick process. In my opinion, the net player has the best perspective on what is happening and what should be done to correct any problems. By making it clear that I want the net player to propose the strategy, I reduce the amount of time needed to arrive at the key decisions.