After doing this for almost 2 weeks, it's pretty clear that the droprate from CEs is 20% and the droprate from FATEs is 5%. We are way beyond the margin of error now. The droprate from CEs is more than 3 times higher than FATEs and it's not even close.

The main issue is really that there are some areas in OC that only have 1 CE. Despite how much Atma I have, I have no Orpiment, because it's just FATEs, a pot FATE or 2 very rarely spawned CEs. I think there is one of them I have never seen actually.