A bow with power and an arrow of harming takes the same amount of health as a bow without enchant.

What I expected to happen was...:

A bow with power and an arrow of harming takes more amount of health than a bow without enchant.

What actually happened was...:
A bow with power and an arrow of harming takes the same amount of health as a bow without enchant.

Steps to Reproduce:
1. shoot bow with enchant of power and note damage.
2. shoot bow with enchant of power with arrow of harming and note damage.
3. shoot bow without enchant of power with arrow of harming and note damage.