Hi @Daniel_Clarke ,
You are correct that exchange rates are not tied to a date range. They are not dynamic, so when you set an exchange rate, it applies to all financial data within the system, and you need to manually update it whenever there are changes in exchange rates. This means that the rates are not automatically adjusted for historical data; they are applied consistently across all projects and time periods.
A custom field could allow you to keep track of or display exchange rates based on certain time periods. The custom field could look at the year, quarter, or month of a date on the object it has been added to and display the applicable exchange rate. You can then use the rate in a calculation to display historical conversions.
Please let me know if you have any questions.
Thanks,
Nathan