Some question in calculating skill damage

1. Skill "Darkness Mastery" of luminous says "Additionally, Death Scythe ATT: +100%". What does this mean? Does it means the damage of Death Scythe is 100% more(230%+100%)? Or the damage of Death Scythe is 2 times?
2. Similarly, "Apocalypse - Reinforce" says increases Apocalypse's damage. Does it means the damage of each hit is 340%+20% or 340% times 1.2?

They're confusing me since the damage in skill is also in percentage. When they say increased by a percentage I am not quite sure what they mean.

Thanks

Can't remember about Death Scythe. Used it too little although it has a rather interesting hitbox mechanic.

All Reinforce Hypers add as a multiplier that is combined with +%Boss and +%DMG. i.e. It's 340%*1.2 without any potential lines, and if you already have 30%Boss from somewhere, then it will be 340%*1.5.

Hadriel

Thank you for ur replying, hadriel.
Problem solved

Now I am closing the thread. Thanks guys.