If you use multicurrency accounting, you can enter exchange rate information for vendors who do not use the functional currency.
When you select a vendor who does not use the functional currency, a Rates tab appears in the transaction screen. This tab displays the vendor's default rate type, the rate date that corresponds to the document date, and the exchange rate for the rate date. You can enter different information for each transaction.
Exchange Rates for Retainage Amounts
If you are entering a transaction with retainage, you specify on the Retainage tab whether the retainage invoice uses the same exchange rate as the original document or the current rate.