How exaclty does %Damage to Demons work?

[Cyath]

Where exactly in the total damage calculation is the %Damage to Demons from axes and weapons like Goldstrike Arch added? At the end? Somewhere in the middle? If I had an axe (150%) and Laying of Hands (350%) would I get 5 times the amount of damage I normally would deal to another enemy on a demon?

I'm no good at numbers and calculations of this sort, so hopefully the gurus here can help me out on this one. ^_^ Thanks in advance!