From The Digital Reader:
Ever since July 2015 Amazon has been paying authors and publishers with works in Kindle Unlimited by the page, and on 1 February 2016 Amazon adjusted how it calculated the page size.
Amazon quietly announced on the KDP support forums on Monday that it had developed a new algorithm for calculating the Kindle Edition Normalized Page Count, or KENPC.
The retailer said that the new method, which has been dubbed KENPC v2.0, “makes a number of improvements to how we standardize font, line height, and spacing used to normalize the length of each book relative to one another. This change will impact the KENPC of some titles while others will remain unchanged. The average KENPC will change less than 5%, although individual books’ changes may be larger or smaller. The new KENPC approach will be applied uniformly to all KDP Select books and all versions of those books.”
. . . .
In related news, Amazon has also added a cap on the maximum number of pages an author can earn from a single reader in a single title (3,000 Kindle Edition Normalized Pages).
Amazon says that only the very longest books will be affected, and given that authors have reported that, say, a 300 page paperback has a KENPC of around 500 to 600 and that a box set ran to around 2,000, I would bet Amazon is correct in that regard.
Link to the rest at The Digital Reader and thanks to Valerie for the tip.