The rates themselves show on your receipts? Are you using some sort of plug-in? Could you forward me a receipt at edwin@stripe.com?
For the conversion itself, we automatically convert from whatever currency you've accepted the payment in, then send it to your JPY bank account. The conversion rate is the average of whatever people are buying and selling the currency at that hour, but some financial institutions add a small markup on top of that along the way.
The rates were not showing on our receipts. They were showing on the bank statements of our customers. They were charged an extra 2 EUR by their banks as a FOREX fee on the Tomotcha payment, on a line showing the USD/EUR forex rate, despite us charging in EUR. Very weird. That issue was only ever reported by two customers in France.
This is on top of my head, but I will forward you the relevant and exact information.
For the conversion itself, we automatically convert from whatever currency you've accepted the payment in, then send it to your JPY bank account. The conversion rate is the average of whatever people are buying and selling the currency at that hour, but some financial institutions add a small markup on top of that along the way.