One thing pisses me off is cards charging a Non sterling transfer fee. I'd have expected them to make money on the exchange rate, or be big enough that they can handle currencies without such silly fees to be honest. Even more so when it is someone like American Express, that, well are American, and I am paying something in American dollars. You would think they could handle dollars.
But I have recently discovered something slightly odd.
Using my VISA debit I was charged...
AMOUNT IN USD 206.87 ON 28 JUN VISA 1.269999 FINAL GBP AMOUNT INCLUDES NON-STERLING TRANS FEE £4.48 = £167.37
But when I was then refunded, it looks like...
AMOUNT IN USD 206.87 ON 30 JUN VISA 1.2669 FINAL GBP AMOUNT INCLUDES NON-STERLING TRANS FEE £4.49 = £158.80
This means I was charged for the refund, and oddly charged at a higher rate (by 1p).
Using my Amex I was charged... (different day, I have not compared exchange rates)
71.15 UNITED STATES DOLLAR, Non-sterling transaction fee: £1.68, Exchange rate: 1.2687 = £57.76
But when I was then refunded... (next day)
71.15 UNITED STATES DOLLAR = £57.82
VISA charge the non sterling fee on charge and refund, but Amex do not. Indeed it seems they effectively refund the non sterling admin fee.
VISAs fee appears to be around 2.7%, Amex fee appears to be around 2.9%, very similar.
It is actually in my companies best interests if I pay for these on my personal Amex and claim on expenses, if there is any chance of a refund (which happens quite a lot if I have arguments with JLCPCB, for example).