There is usually a fixed rate for converting cryptocurrencies in exchanges. There is no such thing as a fixed price in the market except for stable coins. Therefore, the owners of exchange offices must add to their commission to cover market fluctuations. This is a traditional method in old exchange offices. There is a new way to reduce service costs, which may not seem pleasant at first glance, it is called market price. In this way, it is vague for us because we do not know exactly how much currency we receive. While the amount of currency received in the same conditions is more than the traditional method. One of the few exchanges that offers this service is Exchange Exramz. I suggest you visit its page https://exramz.com. It also provides the ability to convert Perfect Money.