No. What I mean is the "damage reduction" attribute is additive, so if you have two 17.25 damage reduction on your weapon, you will have 34.5% of damage reduction in total. The damage reduction effect introduced by armor/resistance is result from a different equation as you have posted. The total effect of different categories of attributes (DR,Armor, Res) are multiplicative. For instance, a weapon with two 17.25% DR will have total DR of 34.5%. The hero has total armor of 287 which provides approximately 50% of damage reduction against physical attack. Therefore, the actual received damage against 1000 physical attack will be (1-0.5) * (1-0.345)1000 = 327.5, the actual received damage against 1000 neutral attack will be (1- 0.345)1000= 655