U2 Best of 3????????????

Here's my question, ok U2 Best of 1 is from 1980-1990, right? Right. Best of 2 would then be, I'm assuming, from 1991-Present. Soooooooooooo what about Best of 3? What is this album going to consist of? I was under the impression that these three albums would all be released within the same time frame. Maybe I'm wrong I don't know but why would U2 sign a contract for a Best of Album for 10 years in the future? They may have a 7 album contract but that doesn't mean they're going to produce hits, well we all know they will but what I'm saying is why would they sign a contract for so far into the future? Who knows what's going to happen?