Pot mapping is the answer unless you have an OS. It is very vague in the manuals how much the shaping affects the bus and because it is either on or off, there is no control over the amount of shaping other than the overall amount.
Is there a pedal or something else connected to the MOD2 input on the back?
If there is for example a pedal connected that isn’t fully pressed down, you get only a small range of modulation, because only a small voltage is then used and shaped by the velocity.
But the max modulation depth by velocity is really a bit low.