You can view and change the rates being used for foreign exchange on the Load Data tab.

Rules used for historic figures:

When translating from accounts in one currency to another (as from a foreign subsidiary to a consolidated parent account), IFRS guidelines are used.

Specifically:

• the P&L uses the average monthly exchange rate in the month being reported. This is calculated using the average daily rate for every day of the month divided by the number of days in the month.
• the Balance Sheet uses the average daily exchange rate on the last day of the month.

Rates are to four significant digits sourced from Open Exchange Rates, www.openexchangerates.org.

Rules used for Budget:

• By default, the Budget uses the exchange rate from the most recent completed actual month.  This can be changed on the Load Data page using "Budget FX Rates"

Rules used for Invoices and Bills

• Invoices and bills are translated from issue currency into your accounting system's reporting system using rates generated by your accounting system.  These are generally the rates applicable on the date the bill or invoice was created.  See your accounting system for more details.
• On the consolidated Customers page, reports use the above rate, then use "Invoice FX Rates" to translate invoices to the parent currency, based on issue month.  Note that, by default, these rates are the same as the P&L rates for actuals - that is, the average for the month.

See this article for how to change the exchange rates being used in ScaleXP.