Sounds pretty reasonable. And with boosted droprates that would become very attainable. Do you have any theory as to how other, non-Castle dungeons compare to those numbers?
They also compiled stuff from the other dungeons that rotation, and I was also seeing drop rates of about 1%. If I combined all runs across those five dungeons into one pool (almost 4000 runs!) ...it was still close to 1%.
I should probably ask the guy if I can at least take images of the spreadsheet, so y'all can get a better grasp of the numbers.
EDIT: random musings:
Four 45% gravities = 90.849375% HP removed
Three 45% gravities = 83.3625% HP removed
Two 45% gravities = 69.75% HP removed
Four 35% gravities = 82.149375% HP removed
Three 35% gravities = 72.5375% HP removed
Two 35% gravities = 57.75% HP removed
Four 30% gravities = 75.99% HP removed
Three 30% gravities = 65.7% HP removed
Two 30% gravities = 51% HP removed
Two 45% gravities are stronger than three 30%'s, so I wonder if this means another boon for Lucifer with the additional sub slot?