Got it!
It must be customers with multiple loans!
I doubt if that is the reason for the apparent anomaly. The anomaly result from Cashfirst being a new business, so the loan book has not had sufficient time to average into a steady-state for a set number of customers.
The average loan of $2,400 relates to the value on the day the deal is done. Consequently, the average loan outstanding is a smaller value, and those close to expiry much smaller. The impact on the loan book of expired loans is small, because a year ago they would on average have repaid most of the loan. In contrast, if in the last 12 months Cashfirst signed up as many $2,400-a-pop new customers to replace those that expired in that period, their relative newness would occasion the impact on the loan book to be roughly $2,000 per customer. Also, I think the average loan some three years ago was less than $2,400, which would exaggerate the anomaly, and a spurt of new loans recently would do likewise.