Calculating %increase from boss neb + other calculations/questions

Dual Blade doesn't have any %damage that affects damage range, but they get 60% from Final Cut. I had 10% from Kanna, however much is on Hero's Gloves (20%?), 9% on my Dagger, 9% on Katara. All that + another 10% from Demon Avenger now.

So I believe hadriel's math is correct (I double checked them as well) but the numbers he used may or may not be correct (point #1 in OP) as the multiplier on bosses comes from

1 + total_damage% + boss_damage% + hyper

While in your original thread he only used

1 + boss_damage% + hyper