In the “regular” Velocity Tracker metadevice, you have Dest, Dest Min, Dest Max, scaling
In the modulation version of the Velocity Tracker metadevice, it behaves like a numeric operand only – you can’t map it to a downstream parameter.
For example, I was looking to vary the decay of an AHDSR via a Velocity Tracker. I couldn’t do that.
I could wire a Velocity Tracker to a macro via *Instr. Macros, and then wire the macro to the AHDSR “Decay” parameter. And that works really well for monophonic playback, I’ll use the living daylights out of it for that purpose 
But as soon as samples begin to overlap, the lack of per-sample velocity-tracking becomes noticeable e.g. a loud note held-down while a quiet one plays in the middle modifies both envelopes to short-decay.
Really ghetto interrim solution (don’t have time to unbreak ‘clamp input velocity’ functionality in this mock):
