set gives normal building production with -25% pastures
however, less POWERED pastures obviously results in less production of the pastures.
e.g., 4 alpaca farms with 4 powered pastures each produce 4 saltpetre:
but with the set applied, only 3 powered pastures per farm, so:
in effect, while benefiting the main building, the set now PENALIZES the powered pastures.
and you can't simply add productivity to compensate:
alpacas have 4 pastures originally, 3 with the set -- so +1/3
new world cattle farms have 6 pastures originally, 5 with the set -- so +1/5
even worse, if you first build the farms THEN apply the set, the farms already have 4 powered pastures -- which keep producing even though they are "over" the limit:
BUT if you apply the set first or delete a pasture, you're now limited to 3: