Currency conversion applied to reporting can include many different scenarios.
- Data in multiple currencies, report with a single currency
- Data in multiple currencies, report with multiple currencies
- Data in a single currency, report with multiple currencies
The rule of thumb is to apply the currency exchange conversion upfront. Therefore, it is a good idea to solve all the scenarios requiring a single currency in the report by converting all amounts at the time of data import into the data model. When you need to create a report in multiple currencies, computing data in advance could be challenging and expensive. Therefore, a dynamic solution based on DAX measures and a properly designed data model makes more sense.