^
Estimated page count exists on Kindle books which don't have a physical print edition. The Dyachenko book you've linked is digital-only, because it's translated from the original Russian and was never published in print in English, and they self-published the KDP version and haven't done a CreateSpace paperback of it yet.
By contrast, here's
The Scar, a title by the same authors, which has been picked up in English translation and printed by Tor Books, which thus gives it a physical copy for the basis of the "Real Page Numbers" it says it has.