Auto Payments are calculated based on the financial breakdown at the time of the reservation's confirmation and do not recalculate if any changes are made to the reservation’s financials.
If a reservation has been updated, cancel the remaining Auto Payments and edit the Auto Payment rules to schedule new payments to be collected in order to avoid payment discrepancies. You can also cancel the existing Auto Payment rules and collect the payment manually.
When setting up more than one auto payment rule for a listing, set the final rule as "Collect rest of payment" rather than a percentage of the payment. If the reservation total is altered after the first guest payment is made, the entire remaining amount will be accounted for by the Auto Payment rule, and your guest will not be undercharged or overcharged.