Hi,
I don't find any issue with the code. Even if you put IDATE in the filter to accept the user input, at least 3 months data should be displayed for both the keyfigures i.e 01.2013 to 03.2013.
On what basis you have arrived for the conclusion that the data is displayed for only 2 months?
Have you checked the targets of the query whether data presents or not?
Also on what kind of infoprovider the query has been built so that you may get some clue.
Regards,
Satya.