Your coach just needs to have an idea to what you want to do before the match, if you take time to actually write/type/mark anything, you will have to take your eyes off the field and thats time wasted that you could be scoring. Ken always tells us that its the coaches job to know what should happen next because hes the drivers/operators "eyes" for the rest of the field (He likes to tell us what to do
). If you can find a quick way of doing it then more power to you, but i think you should just practice all the different ways of scoring and whats needed in each situation.