Unitary means that a currency (or a country) has only one exchange rate, which is commonly used in all international economic transactions in that country.
A single exchange rate is the symmetry of a compound exchange rate.
In some countries, there is only one official exchange rate and everything is settled at the same exchange rate.
Under the single exchange rate system, banks do not charge customers any service charge if they suspend double quotes for buying and selling various foreign currencies in foreign exchange transactions.
If only a single quote for each type of foreign exchange is suspended, the bank will use the same quote when buying and selling foreign exchange, and since it does not, it must charge the customer service fee at the specified rate one by one.
