do hub -10% workforce buff stack?

[Serpent]

yep that's the question. i saw different type like fuel and material hub show separately.
but i don't know if i can just build fuel hub around deep mine site to reduce more workforce.

[Adriaman]

Yes for the stacking.

(I am not 100% sure) but they seem to apply only on the base demand, not the demand of the buildings. So most of the time not really worth it unless you have a big surplus of another resource.