So, you earn +80 in barter skill if you have tagged Barter and chose Salesman perk ?
Yes. You can do math.
Nope, the tagged bonus to perks is a bad idea. Imagine that you have 140 barter (tagged) and take the salesmen perk. Boom! 180 Barter! (yes, bonuses from perks aren't lowered after you reach 101% in a skill
If you want to make enemies, try to change something.