Looks like I misread your comment when posting my other reply (I was talking about one-to-one). Sorry about that.
I'm not sure what the few/many distinction is about, but I can guess: if they only said "one-to-many" it could be unclear whether "many" means "more than one" or "some sufficiently large number", so they include "few" to remove ambiguity. Said another way: "one-to-few and one-to-many" is just a different way to say "one to more than one". As far as I can tell the new guidelines don't use the few/many distinction anywhere and only mention both in this one sentence.
> If your app enables the purchase of realtime person-to-person experiences between two individuals (for example tutoring students, medical consultations, real estate tours, or fitness training), you may use purchase methods other than in-app purchase to collect those payments.
So you can avoid the Apple tax if you're a private tutor.
However it looks like I misread blueicecubes' comment. They were asking about one-to-few vs one-to-many, but I talked about one-to-one.
I'm not sure what the few/many distinction is about, but I can guess: if they only said "one-to-many" it could be unclear whether "many" means "more than one" or "some sufficiently large number", so they include "few" to remove ambiguity. Said another way: "one-to-few and one-to-many" is just a different way to say "one to more than one". As far as I can tell the new guidelines don't use the few/many distinction anywhere and only mention both in this one sentence.