does Black Orc Forge stack?

[tripleAron]

So this building can only be build on settlements with the resource Iron present.
The building gives 20% discount when recruiting Black Orcs.
Does this discount stack if i have multiple settlements with Iron and the Black Orc Forge present?
Because if it does and i build 5 does it mean i have a 100% discount???

[Gaizokubanou]

All building effects (minus ones that unlock research (because research is province-less)) apply only to the province.

[tripleAron]

Ah thanks, it doesnt say in the game text that it only applies to the province