Stating the obvious here but the difference from monetising music streaming services is that you don't consume the content over a live connection hence the current Amazon model is just plain flawed.

I personally would adapt to something much much simpler than guessing thousands of page views sharing thousandths of pennies.

KU subscribers pay £10 pm for up to 10 books at a time. After the commission just share the remaining £7 amongst the other books held during the month. None of this funky pageview stuff.

That way the scammers would only be taking from their own subscription fees.