Hi Mahesh,
So you date format for Jan starts at '01012013 or 1012013?
Just mantain the property in the format it starts with.
For Jan u drill through working fine. But for Feb is it working fine for Feb but not for Jan. Do you mean when you try to drill through for Feb you are expecting to get both Jan and Feb values?
If you give more detail it will help us.
Regards,
Kalyan.