1. If the order has products flagged with UseDeliveryDateAsCurrencyConversionDate (typically used for fuel uplifts) then the most recent uplift drives the transaction date
2. Else if the order is invoiced, the transaction date is set to the invoice date
3. Else the transaction date is set to the current local time at the order's handling station. As you can't predict future rates, this is your best value.

Rate changes between payment and transaction dates.

When a credit card payment is made for an order, it's usually paid in full, reducing the amount due to zero. However, there may be a delay of a day or more before an invoice is generated. An order remains editable during this period.

• An order is considered finalized and unchangeable only when an invoice is created.
• However, there's a brief window during which the amount due could increase due to a new exchange rate.
• To prevent this, FBO One ensures the amount due is set to zero when the order is recalculated with a different transaction date for the last payment, but only if the last payment initially resulted in a zero amount due.