By design, the Multicloud report will always show costs in USD. The costs for each cloud will be converted from whichever currency they use to USD. The platform updates the currency conversion rate during every report processing.
The platform keeps a record of the currency conversion rates for the past 13 months. For a Cost History report (daily/weekly/monthly) in a currency other than USD, the cost is defined using currency conversion rates of the corresponding days in the selected interval and updates the Multicloud Cost History report.
Currently, there isn't a way to see the specific conversion rate used on the report.