MapleStory Unlimited: Ignore Mob Defence?

As a Hero, let's say I have max Combat Mastery that is 50% ignore defense, Leafre set which is 30% ignore defense, as well as Luminous link skill which is 15% if my Luminous is level 120+.

Does that mean ignore 50% of 70% = 35%, ignore 30% of 35% = 24.5%, and ignore 15% of 24.5% = 20.825% of the damage I deal will be ignored?

more like your damage would be reduced by 20.825.

did i mention i hate this system?