Yes. Anytime you use your personal or business credit card while you are overseas or to make an online purchase from a company outside Barbados, e.g. Amazon or eBay, you will have to pay the FXF.
The FXF will be calculated based on the Barbados value and that Barbados value will be calculated using the exchange rate on the date your bank posted the transaction. As a result, the exchange rate on the date you pay your credit card bill will not affect how much you pay for the FXF.
Below is an example of credit card statement showing the posting date for each transaction:
N.B. Even if you opt to be charged in Barbados dollars when you purchase an item with your credit card, you will still have to pay the FXF. This is because even with this option, your bank must still use foreign currency to pay the company you purchased the item(s) from.