True Aim and ACaEBG have a combined cost of -4 Refresh. True Aim must be at least -1 and thus ACaEBG cannot be higher then -3. Given that True Aim is exactly designed (notably more powerful then a stunt, but with two moderate drawbacks, must use *that* weapon and must be in accordance with purpose) according to the RAW guideline for building a -1 power, assigning the remaining -3 to ACaEBG is logical.
No, they have a combined Refresh of -5 (as Sanctaphrax points out).
Edit: sorry, didn't realize you had costed "Holy" as -1 and quietly dropped it from the equation.
YS 168: "
Discount Already Applied. As an Item of Power, the sword already includes the one-time discount (page 167). This means that if the character possesses more than one Item of Power, the one-time discount will not apply on that second item. If the Sword of the Cross is the second or subsequent artifact the character gains, the refresh cost is –5."
The Item of Power discount for the Sword is -2, not -1, because it is big and bulky.
Also, the "Divine Purpose" trapping is a clear limitation, but provides no listed deduction. So the isolated Refresh value of ACaEBG could be as high as -4 to -6.
Also, some of these things were balanced based on narrative impact and not just point balance. Do you know why Warden Swords are Enchanted Items and not Items of Power? Because no Warden could afford them otherwise.