I've been wondering, and can't seem to get a grasp on the rules on this.

Do you roll for helping/interfering before or after the roll that you want to influence?

So far, the one group I've been playing AW with have gone with after, mainly because ...I'm not sure, we just called it like that and now it's all established. But what do I tell the MC of my new AW group when this comes up? It's a pretty damn crucial difference, and I'm supposed to be the one who knows this stuff.