Billing by request count? Which one?

Hey all,

I’m trying to predict my monthly invoices, but I’m a bit confused about which number is taken into account for monthly billing. In “Workers & Pages” page I see, that so far my workers received 3.15M requests:


But if I take a look at “Billable usage” page, I see - 2M requests (see post #2 screenshot)
Why they differ? Which number is correct? If it’s the 2M, is it possible to retrieve or calculate this number somehow using GraphQL or API?

“Billable usage” data: