Then on my second Simple Action fire? So instead of getting the Usual 4 shots with my guns, I only get 2 shots this IP, but at extra damage. I see it being a fair trade off i think.
I agree it's a fair trade off, and I personally would allow it, but rules wise it doesn't work that way. It all ties down to the way Called Shot is worded: This action must be
immediately followed by a Take Aim, Fire Weapon, Throw Weapon, or Melee Unarmed Attack.
Call Shot is not on the list of actions that must immediately follow a Call Shot, so you can't do them back to back by the rules.
Then again, I personally don't think calling a shot should even be an action. I think players should just be able to choose as many penalties as they want during the Fire Weapon/Throw Weapon/Melee Attack action.