There are so many friggin variables in skiing ; consistency is the objective for which to strive.
ropes, altitude, air temp, water temp, water conditions, size of the engine, maybe the lag of the engine gives you a millisecond and acts like a stretchier rope, or more like perfect pass that let you pull it down a bit, or stiffness in a ski, or torsional stiffness in a ski, or softer tail flex....I think you get the point.
ps: Rico swerved.