Otherwise everything is pretty much in the data, really. You get X drop checks (what you call drop chances) per hit.
This is precisely the point. What causes drop checks is _not_ in the known data. At all. But people keep running miniscule tests and because Maxwell gets to full SBB they assume they know why. I want people to question the assumptions.
When this was proposed months ago, I put this forward (which was in fact happening in FH at the time, to my team):
Let's pretend Maxwell has 66 drops, which is the theory people periodically put out there.
How does this party, even given that, get to full SBB against a single target using all SBBs the prior round?
Duel-SGX - BC cost 30, gen 20
Lucca - BC cost 40, gen 19
Fiora - BC cost 40, gen 16
Elza - BC cost 45, gen 30
Maxwell - BC cost 49, gen 66
Maxwell - BC cost 49, gen 66
Total BC cost 253, gen 217.
Maxwell "being at 66 drops" does not explain it. It's not even close to explaining it.
People keep doing these individual tests on Maxwell, ignoring all other units and all other possibilities. Something gives extra drops, and because people are so focused on Maxwell and what they "know", they ignore the fact that it goes far beyond Maxwell.
I see no reason to believe, given the above, that Maxwell really does have 66 drops.
No, I believe Maxwell still drops 33, and that the other drops account for the rest of their test. But since none of them want to do any testing beyond Maxwell, they have convinced themselves that Maxwell has 66 drops, as in JP.