Objective Analysis: Psychology of using BNPL, page-110

The late fees can NOT exceed the cap of $68 of total late fees (meaning both $10 & $7 late fees together)
or 25% of the order. Whichever is less!!

Try reading the T&Cs instead of shooting of your mouth:

If a payment is not processed on or before the due date, late fees will apply – initial $10 late fee, and a further $7 if the payment remains unpaid 7 days after the due date.

So a minimum of $17 if you're one week overdue

For each order of $40 or above, the total of the late fees that may be applied are capped at 25% of the original order value or $68, whichever is less.

https://www.afterpay.com/en-AU/terms-of-service

The fees are per order (not the total). They do not include extra late fees for being 7 days overdue.