I don't know if anyone has addressed this before, but did you look at the setting for velocity on the keybed? Sometimes, the curve is set so that the highest velocities really need to be spanked to get the volume. I set mine at a medium hardness ... I hate the thought of hitting these plastic, anemic keys too hard. I cut my teeth on a Rhodes, so I'm used to digging in, but with today's arrangers .... not many have the rigth resistance to really "pound the ivories" (plastics)

Try setting your velocity curve to a softer touch.