Sorry, I wasn't saying that, I was asking if that was what she/he meant. That was why I was asking for confirmation. Going back and re-reading the post I see that was not what they were saying at all. Your post of the snippet is exactly what BMO Mastercard does.I'm not 100% sure about this. When I make a purchase on my Rogers MasterCard, the pending amount and the eventual posted amount are never the same, indicating that different rates are used. I've never looked into what the difference was from, but I suspect they are using the rates on the day the transactions are posted.
Here is a snippet from Rogers FAQ, indicating that it uses the rate on the day the transaction is posted, not the transaction date:
All purchases made in a foreign currency are converted to Canadian dollars at the rate established by Mastercard® International on the date that your purchase is posted to your account, plus a foreign transaction fee equal to 2.5% of the transaction amount after it has been converted to Canadian dollars. To verify the Mastercard® exchange rate before you make your purchase, please visit: www.mastercard.com/global/currencyconversion.
Again, sorry for the confusion.