IBM Cognos Controller does not support mixing weekly and monthly actualities in report generator reports

When you run the report for a weekly actuality and for a period larger than 12 (for example, 1213WE) and use a relative period reference (for example, P001) for a monthly actuality (for example, AC), then the translated period is 1301 instead of 1201.

The solution is to insert a column in the report layout in the spreadsheet. Use an if-function to use the correct data that is based on the period number.