You could acquire the Outhouse for free that way. Because it saves you 1(x) for each Railroad icon of the building you buy and the Outhouse has 3 Railroad icons, and cost 3 influence.
Ok, that is the way we've been playing it. But it goes against the wording slightly.
With multiple industry icons I see the card saying this...
Pay 1 less (X) per
If three icons then: Pay 3 less (X) per -> Therefore Pay (X)(X)(X) less.
- Meaning you could only get a discount on one type of resource, so you'd still have to pay for the other two.
Rather than this...
Pay 1(X) less per
If three icons then: Pay 3(X) less per -> Means you get a full discount of 3 of any type of resources for purchasing that building.
Not sure I get why this was worded different from the others if it is following the same rules as the others.
Thanks for the official answer though!