The current Simulationcraft version doesn't appear to correctly model Insignia for Assassination. In particular, Simulationcraft models Insignia as if it always did the same percentage of the Mutilate's damage whereas in-game it takes pre-Vendetta damage, resulting in significantly lower Insignia damage. You can clearly see this when looking at the total damage contribution of Insignia but also when looking at the logs in detail:
In-game:
00:00:07.432 Rogue Mutilate Krosus 211720
00:00:07.432 Rogue Mutilate Off-Hand Krosus 106134
00:00:07.458 Rogue Insignia of Ravenholdt Krosus 66296
00:00:07.458 Rogue Insignia of Ravenholdt Krosus 33234
00:00:07.827 Krosus is afflicted by Vendetta from Rogue
00:00:08.430 Rogue Mutilate Krosus 147881
00:00:08.430 Rogue Mutilate Off-Hand Krosus 68424
00:00:08.454 Rogue Insignia of Ravenholdt Krosus 71240
00:00:08.454 Rogue Insignia of Ravenholdt Krosus 32962
Simulationcraft:
3.014 Rogue mutilate_mh hits Fluffy_Pillow for 214429 physical damage (crit)
3.014 Rogue insignia_of_ravenholdt hits Fluffy_Pillow for 34424 shadow damage (hit)
3.014 Rogue mutilate_oh hits Fluffy_Pillow for 114690 physical damage (crit)
3.014 Rogue insignia_of_ravenholdt hits Fluffy_Pillow for 18412 shadow damage (hit)
4.018 Fluffy_Pillow gains vendetta_1 ( value=0.30 )
5.021 Rogue mutilate_mh hits Fluffy_Pillow for 170481 physical damage (hit)
5.021 Rogue insignia_of_ravenholdt hits Fluffy_Pillow for 54737 shadow damage (hit)
5.021 Rogue mutilate_oh hits Fluffy_Pillow for 85236 physical damage (hit)
5.021 Rogue insignia_of_ravenholdt hits Fluffy_Pillow for 27367 shadow damage (hit)
As you can see, Simulationcraft has Insignia damage at a constant ~30% no matter if Vendetta is up. If you look at in-game logs however, Insignia damage drops to ~23% of Mutilate's damage which is ~30% of the pre-Vendetta damage. Thus it appears that Insignia is calculated without any debuffs taken into account in-game which is not properly reflected in Simulationcraft.
The current Simulationcraft version doesn't appear to correctly model Insignia for Assassination. In particular, Simulationcraft models Insignia as if it always did the same percentage of the Mutilate's damage whereas in-game it takes pre-Vendetta damage, resulting in significantly lower Insignia damage. You can clearly see this when looking at the total damage contribution of Insignia but also when looking at the logs in detail:
In-game:
00:00:07.432 Rogue Mutilate Krosus 211720
00:00:07.432 Rogue Mutilate Off-Hand Krosus 106134
00:00:07.458 Rogue Insignia of Ravenholdt Krosus 66296
00:00:07.458 Rogue Insignia of Ravenholdt Krosus 33234
00:00:07.827 Krosus is afflicted by Vendetta from Rogue
00:00:08.430 Rogue Mutilate Krosus 147881
00:00:08.430 Rogue Mutilate Off-Hand Krosus 68424
00:00:08.454 Rogue Insignia of Ravenholdt Krosus 71240
00:00:08.454 Rogue Insignia of Ravenholdt Krosus 32962
Simulationcraft:
3.014 Rogue mutilate_mh hits Fluffy_Pillow for 214429 physical damage (crit)
3.014 Rogue insignia_of_ravenholdt hits Fluffy_Pillow for 34424 shadow damage (hit)
3.014 Rogue mutilate_oh hits Fluffy_Pillow for 114690 physical damage (crit)
3.014 Rogue insignia_of_ravenholdt hits Fluffy_Pillow for 18412 shadow damage (hit)
4.018 Fluffy_Pillow gains vendetta_1 ( value=0.30 )
5.021 Rogue mutilate_mh hits Fluffy_Pillow for 170481 physical damage (hit)
5.021 Rogue insignia_of_ravenholdt hits Fluffy_Pillow for 54737 shadow damage (hit)
5.021 Rogue mutilate_oh hits Fluffy_Pillow for 85236 physical damage (hit)
5.021 Rogue insignia_of_ravenholdt hits Fluffy_Pillow for 27367 shadow damage (hit)
As you can see, Simulationcraft has Insignia damage at a constant ~30% no matter if Vendetta is up. If you look at in-game logs however, Insignia damage drops to ~23% of Mutilate's damage which is ~30% of the pre-Vendetta damage. Thus it appears that Insignia is calculated without any debuffs taken into account in-game which is not properly reflected in Simulationcraft.