LAST Function Query

Hi All,

I am running Cognos 10.2.1 on ISAPI module on SQL Server 2012 on a Winodws 2008 server

In Framework Manager I have the following:

Namespace1 with the following two Regular Dimensions:
Dim1 = MIS Time with 3 levels i.e. Year, Quarter and Month.
Dim2 = Months on Books with just one level i.e. Months on Books.

Now, Namespace2 has all the measures which are coming from my Aggragate table.

My Requirement:
Use LAST function to display the measure, $Revenue.

What I have done:
For the measure, $Revenue, in the FM, I have added an aggregate rule with following details:
Dimension = Dim1
Aggregation Rule = LAST

In Report Studio, when I display Revenue by Year/Quarter/Month, I get the desired result.
But when I display Revenue by Months on Books, I get an empty table. NO DATA.

How do I get to show the correct data by Months on Books along with Year/Quarter/Month?

Any advice/suggestion will be highly appreciated.

Thanks n Regards