Multicurrency Configuration in Workforce with Fixed USD Expenditure

Use Case: Multicurrency configuration in Oracle EPBCS with USD as the reporting currency and various input currencies, such as EUR. Most employee-related expenses, like salaries and benefits, are expressed in the input currency. However, there is a fixed per capita monthly expenditure that is a fixed USD amount. Is this supported?

Question 1: If I code the fixed USD amount in terms of the input currency, it will vary month-to-month due to exchange rate conversions. One solution could be to express this fixed cost based on the currency exchange rate for the month, updating it each month when the exchange rate is known to achieve the desired USD equivalent. Would this approach work?