I am not an expert on banking transactions, but based on the international credit card transaction model that I understand:

Merchant -> acquirer bank -> network (Visa, MC) -> issuer bank -> card holder

The merchant wants to be credited the correct amount in local currency for the service, minus the swipe fee charged by the acquirer bank;
Acquirer wants to be credited the correct amount in local currency for the transaction;
In case a no FTF card, the issuer bank is charged the appropriate amount in card currency + 1%, which it absorbs for the card holder;
Card holder is debited the appropriate amount in card currency, and the rate is shown on the statement.

In this loop, the network does all the currency conversion and charges 1% for the service. Each side sees the transaction as a normal local currency transaction.

Therefore, anyone using DCC is just purely trying to rip people off, and a lot of these DCC people deceive.

Of course, that is based on the assumption that my model is accurate, which I don't have the confidence. But if I build a credit card network, it would be looking like this.