You know I have never considered +lightning % in d2 that way
It is adding to my total % added rather than just a flat 30% when I equip the weapon.
Your explanation makes alot of sense, though 5/5 facets are shockingly cheap this Ladder lol, still 1 is more than a cm tho :P
Yeah any source of %enhanced damage (whether its physical, light, cold, fire...) are additional
So fire & light sorc have already nearly 500% from mastery
So -30/30 sword would be +530% and -30% which is worse than +500 -35 vs monster with high light res
Also since cold mastery is only -cold res the +% cold dmg is really important, but also the -res since the mastery only applies at 1/5th effectiveness on sundered monster