very interessting question! I guess no one has an satisfying answer to this because they are not specified anywhere. As far as I understand this, it's just the hardness from a soft (0) to a hard (10) velocity behavior.
BTW: Most of the Artuia soft-synths don't support velocity changes. Not even the Laboratory software. Dosn't matter what settings you choose, the pads as well as the keys are not reacting to different velocity, they are only adjustable by volume. Actually only the Wurlitzer V does support different velocity settings and there you can adjust the velocity curve on the software.
Note: I'm not that much experienced as a keyboarder, but this is what I found out.