I get the impression you’re not really sure what’s going on here @killerpirate, you’ve made a heap of posts recently and I assume you’re still learning.
All of the recommendations Best in Bags gives are based off simulated data, there’s no feelycraft or napkin math involved.
You setup your talents and BiB gives you a “solution” based on the pre-simulated data.
If you don’t like the result you can lock items, conduits or soulbinds in or go further and push it towards secondary stats you prefer, you can also weight the conduits in differently. I know you’re aware of that as your snapshot has the conduits weighted, although they’re all rated the same so it hasn’t really done anything.
The more you modify it the more distorted the results will be.
As Swol has mentioned you can run simulations yourself to test things out.
I ran a couple of simulations from data loaded via your snapshot.
7,468 HPS 1.13 Ally Deaths - your gear as imported
7,782 HPS 0.36 Ally Deaths - BiB default result
So BiB is getting slightly more healing and a lower chance of anyone dying.
It’s set to be a +10 Tyrannical Bolstering fight, the seasonal affix isn’t implemented.
I ran those sims with the log option selected so you can dissect it to see what it was doing.
However before that you probably (should?) want to know what the script is doing.
There are two scripts involved, one is for the encounter and the other is the character one, the rotation logic or APL, if that naming helps you frame them in your mind better.
If you look in the Theorycraft Wiki you can find both. The easiest way to get there is to click the view/edit link next to where you start the sim.

Mythic+ healing script which is quite well commented so you can work out what is going on.
You’ll notice that it is modeling the Moroes encounter from Return to Karazhan.
This fight was chosen as it’s very hard to heal when it’s at the limit of your gear and group. Eventually you’ll run out of mana and wipe if the group doesn’t kill him quickly enough.
Now you know what the script does you can modify the player script to try and get a better result.
If you do I am quite confident that Swol will incorporate your improvements and the data will be recalculated so it works in BiB for everyone.
To do that you click the Copy link at the top of the page, then you can modify the decision making steps in the script to mimic how you play. You can then see if you can make it better than Swol’s default.
Whether you like the encounter script or not is irrelevant as it’s the same for each APL you test against it, this is the missing piece that WoW healing tools have been missing for a long time.
It is possible to modify the encounter script but it is not as easy to do as the APL, the learning curve is very steep and I mean VERY steep. I modified the old Heroic script for Garothi Worldbreaker, first boss in Antorus, to model the Mythic changes as I was interested to see how I was performing on the fight, also the rest of the raid but it was mostly a learning exercise for me.
It was pretty accurate but it took me a long time to get working, much longer than it took to beat but I kept at it to better understand how the simulator worked.