Board Thread:General Discussion/@comment-36015663-20181018164003/@comment-36094989-20181021012906

Here is my little hypocritical hypothesis: as Habrish has mentioned, the relative ratio of CIs within a collection can affect future drop rate. An extremely uneven collection will skew future drop rates so that the hole becomes perpetual.

another observation: I had much better chance at obtaining even ratios of new collections when Kindle was one of the first platforms to be updated.