UNION ALL change in .prm files for BI 4.1 SP 4 not reflecting for Multi-Source Universe.

Dear All,

I am working on a Multi-Source Universe based on SQL Server 2005 and 2012.

In Webi Query produce "UNION" SQL statements, however we have a requirement to make it produce "UNION ALL" in SQL statements for better performance. 

We do not want to use Custom SQL because that will be difficult to manage and identify also it will not reflect any changes from IDT if updated.

We have already made the following changes in the .prm files as below:

<Parameter Name="UNION">UNION</Parameter>

to

<Parameter Name="UNION">UNION ALL</Parameter>

Changes has been made to OLEDB and SQL .prm files since.

****ISSUE****

The above change is only reflected to single-source universes, however Mulit-Source universe we have does not have any effect on SQL statements neither for existing reports nor new  one.

SAP Note Referred:   1819399 - How to use Union ALL instead of Union in the Web Intelligence Reports?

Any help would be really appreciated.

Thanks,

Satish Soni