I just tried this with a 5 m cube, generated both tets and voronois and then cut them, and it does appear to produce slightly different behaviour.
Tet blocks
model new
block cut set minimum-id 5
geometry import 'test_geometry.stl'
block generate from-geometry
block cut joint-set dip 0 dip-direction 360 spacing 1 ...
number 4 origin 0 0 2 jointset-id 10
Voronoi blocks
model new
block cut set minimum-id 5
geometry import 'test_geometry.stl'
block generate voronoi
block cut joint-set dip 0 dip-direction 360 spacing 1 ...
number 4 origin 0 0 2 jointset-id 10
@jhazzard one for your wisdom, perhaps?