Heavenly Blessed/Wrath of God Att Power Calculation

The tool tip for the “Valor” tripod of the above 2 skills reads:
“Grant’s +15% of your Atk. Power for all party members withing 24 meters for 8.0s. Overall Atk. Power +6%”.
I believe either the tool tip is incorrect or it’s not working as intended.
It seems the calculation is based on your base attack before, before factoring in Engravings that increase Atk Power (such as Cursed Doll, Stabilised Status and Increased Mass).
Could you either fix the calculation or amend the tool tip?