A few people here might be reading too much into those numbers. At most, they serve as a way of gauging how strong a character is at a glance. In-character, they aren't going to do anything.

If you're looking for proper rationalisation, LeeRoy might be able to give you that -- but as they're used solely for guidelines, I personally don't think the rationalisation matters (so long as the actual characters aren't as vague). I guess it should also be said that the tier system being referenced in (most) other threads was from before the new Guild, and wasn't tiered by stats and numbers in the way that this system is.

All in all, I'd really hope that this isn't what's turning yourself (and possibly others) away from this tiny corner of RPG, we're a small enough group as it is =S.