Klarna , Afterpay and Credit Checks, page-66

"To calculate revenue per customer you take the average number of customers over the period (clearly customers that only join later in the FY will contribute less than those that have been there from the start). "

That is just 'cooking the books' by only counting active customers. You have to count every customer - even if they never make another purchase.

The real accounts show each customer is actually 'worth' minus $5 (on average).