Logging the load while monitoring my boost, i notice the load always decreases with the boost and the N75 %.

Out of pure interest, and to help me understand why the boost tails off at ~ 4500 rpm, at which point the load was seen to decrease as well, can someone please explain, or point me to information on, how the ECU calculates the loads % the for the engine.

This also seem to always max at 191.7% ....