The fact that both of these exist implies that IAPs can have a different base territory than the app itself, and that different apps can have different base territories, or even that different IAPs in the same app could have different base territories. Is that actually true?
Yes. For example, I have an US-focused app and a UK-focusd app. I set the base territories to US and UK respectively, so that the pricing is stable in the places where most of the users are. (I've not tried to do this for IAPs, but the same logic applies.)