Am I missing something, or is there some reason why Pack Mule tier 2 and 3 are the same and 4 and 5 are the same other than wording? I am on a save from experimental so maybe that's affecting it. If not, then it makes little sense to have extra tiers to unlock that do nothing. I'd rather the perk cost 2 points if that's why there are extra tiers than to have duplicate tiers. Not that I use Pack Mule but I still think it should be corrected if it isn't caused by my older save.
EDIT: Nevermind. I misunderstood the description of the tiers.