Rolling 12

It looks like the difference between the two measures is in how they handle the filter context. Test 1 is using the "Calculate" function with a filter applied to the "All(Dates)" table, which means it ignores any other filters that may be applied to the report. Test 2 is using the "Calculate" function with a filter applied directly to the "Dates" table, which means it only considers the dates that are currently visible in the report.

To make Test 2 match the results of Test 1, you can change the filter in Test 2 to use the "All" function, like this:

Test 2, Rolling 12 (Revenue) = CALCULATE ( [Revenue €], DATESINPERIOD ( ALL('Dates'), MAX('Dates'[Date]), -12, MONTH ) )

This will make Test 2 ignore any filters that may be applied to the "Dates" table, just like Test 1 does with the "All(Dates)" table.