@Uncle Robin: A not necessarily obvious thing is that you actually control the initial state (e.g., what happens when you open a brand new book).
Each book is a blank slate, there's no cross-book tracking. Instead, there's a setting availableš for the thresholds: a floor (if a page was shown on screen for *less* than this amount, it's not counted in the stats. The intent being ensuring skimming doesn't pollute the stats), and a ceiling (if a page was shown for *more* than this amount, the time is capped to this value. The intent being having spent time in the dictionary/wikipedia/menus/whatever doesn't skew the stats too much).
That's used to seed the initial computation of "time spent reading a page" (at 50% of the cap).
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[1]: This is KOReader's unofficial motto: "there's a setting for it"
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