For the default HC profile, Patchwerk fight, 5 minutes, 10k iterations, the error is ~25. It's a dps loss.
Nicely done, but i still have some ideas. How did you modify the rotation? Does it use AM asap when the 4P Proc occurs?
There might still be possibilities for an intelligent usage of 4P outside of the usual rotation:
Examples:
Proc occurs at 3 AB Stacks - what would happen, if you tell the rotation to only react at >= 3 stacks of AB?
4P proc During PC. You might want to use 4P asap during PC, to proc another one or to prioritize it above AB if duration is about to run out. the 30% Extra Dmg could close the Gap you have shown in the graph - making it worthwile to react.
Another one would be during burn phase. If you are around 70% Mana and decide to stop Casting missiles to finish the burn But have a 4P Proc. This would result in about 7-8 AB casts and not using the 4P Proc.
In those scenarios i still expect a DPS increase. Some of those are not that hard to sim, i try to go for it myself on sunday if you dont like to TLteo.