Pvp Dr Sorc

hi i just want to ask a few questions:

1) does the cold mastery of the sorc lowest the enemies resistance or the % that the orbs gonna pierce thorugh the person

2) anyone got cold skill charm with fhr

it lowers the enemies resist
but in hell it lowers based on 175 instead of 75
you would multiply your % peirce by your number of cold resist
like if i had 0 (100 cold resist)
i would have -90 cold resist if the enemie's cold mastery is 90%

sorry i dont but i have some regular ones for trade