Originally Posted by Lapp

I think you're modeling Executioner slightly incorrectly once you have more than (BossArmor - 840) passive ArPen. Prior to this value, approximating its overall contribution as Uptime% * 840 is correct. However, once you have the aforementioned amount of passive ArPen, Executioner contributes approx. Uptime% * (BossArmor - PassiveArP), not Uptime% * 840 still, as you've modeled.

I don't think this would be a hard to change to implement, and it would help give more accurate comparisons of gear at high levels of passive penetration (approaching Boss Armor, that is), seeing as currently, in your spreadsheet, items with passive penetration on them are heavily favored (whereas in reality, passive penetration becomes ExecUptime% less effective once you have more than BossArmor-840 passive penetration).

Hope you look into this--sorry if any of all that was confusing.