The close date regardless of the opportunity stage is how the converted currency amount calculation on Opportunities is determined when using dated exchange rates and Advanced Currency Management. Dated exchange rates are exchange rates that are tied to specific dates or ranges of dates. Advanced Currency Management is a feature that allows users to enable dated exchange rates and track historical exchange rates in Salesforce. When using dated exchange rates and Advanced Currency Management, the converted currency amount on Opportunities is calculated based on the exchange rate that matches the close date of the Opportunity, regardless of whether the Opportunity is open or closed.