Use the Mr Robot sim to see the difference vs the script used to get the results BiB uses.
Using Raidbots is just using SimC in the cloud. Unless you tell it to do something different it will default to Patchwerk, which is the equivalent of a Target Dummy.
Also if you paste your addon export, from the game, others can see what you’re seeing and can run the sims for you if you’re not sure how.