No, because an opponent doesn’t have “defense” as a generic stat. Opponents have armor and resistance, based on physical or special offense categories. Think of it like critical damage to offense. It impacts physical and special by a certain percentage (150% is the baseline). Defense penetration would increase armor/resistance penetration. Baseline is 0%, but if you add an additional 200%, it becomes 200% of armor/resistance penetration, just like when you add 36% critical damage from a mod you don’t get 36% of 150% critical damage increase, you get 186% critical damage.