How do you define a non-arbitrary page number?
Every ereader software has its own way of calculating that. Although several of them use Adobe's RMSDK, and share the adobe calculation method.
Pagenumbers are a horrendous mess of non-standardization. And that is before considering "which edition are you comparing it to", IF using "real" page numbers at all.
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I think calibre uses a section.paragraph calculation of some sort, which is intended to provide unambiguous citation references.
It isn't a page number.