Source of the Current Exchange Rate field when exposed on reports.

The Current Exchange Rate from the Currency subfolder when exposed on sales reports sources the rate from the exchange rate table under Lists > Accounting > Currency Exchange Rates as of the report generation date regardless of the date or period set on the report footer.

To illustrate consider the following scenario:

Base Currency of the subsidiary is USD.

Report generation date = 8/8/2013

Exchange Rate for USD base to CAD foreign currency on the following dates:

8/1/2013 = 1.20

8/8/2013 = 1.22

8/31/2013 = 1.25

1. Navigate to Reports > Sales > Open Invoices

2. Set the As of field to Aug 2013.

3. Click on Customize to be redirected on the Report Builder.

4. Under Edit Columns, expand Open Invoices and  expose the Current Exchange Rate field found under the first Currency subfolder.

5. Hit Preview.

***Result: The Current Exchange Rate column would show 1.22 for transactions denominated in CAD and 1.00 for transactions denominated in USD.