Pivot View Grand total issue from UNION queries in OBIEE

In OBIEE, if the report has to create based on the pivot view using UNION of 2 or more queries then there is possibility of pivot view grand total issue because server will compute and picks up random value shows in the pivot view grand total.

Issue with grand totals before changes.

To overcome issue, Click on the measures column in the pivot view edit and set aggregation rule to “SUM” instead of “default”.

After setting aggregation rule to "SUM" instead of "default" the results in pivot view Grand total calculates exactly as shown below.