The higher the letter A,B,C the sooner the throttle reacts when the system detects load on the boat. The higher the number 1,2,3 the more aggressive the throttle response is. The sooner the throttle hits you, the sooner it will let go of you once the extra load goes away. The + setting makes the throttle response more aggressive on all letter number combinations, and it has the boat running a 10th of a mile per hour above the set speed before entering the course. B2 is the closest setting that feels the most like perfect pass.