Display and Retrieve only Overall Results in Bex Query

Dear SAP BI members,

My project is using a BO Dashboard for reporting and source for it is BW Bex Query. However, the structure of query is such that Calendar Year/Week is present in columns which is defined with offset to display last 12 week data. And there are 5 keyfigures apart from 1 characteristic in row. The overall result row is displayed at top and calculated as "Counter of all values". The overall output of query is such that it generates lot of cells and gives error - " Result set too large (606762 cells); data retrieval restricted by configuration (maximum = 500000 cells) ". Unfortunately I cannot change the BO part and I have to solve this problem in BW query only. Another point to be noted here is that BO is using only overall result row which is configured to display at top of the report. So basically BO is interested only in top 3 rows (Calweek, keyfigure description, overall result) and rest all data is irrelevant for it. So I now need to find out a way by which I will display only overall results for the query and somehow hide rest of the row/column data. I also tried option of "Calculate single value As - Hide" for all keyfigures but it is still generating same number of empty cells and giving the same above error. So basically this option did not work for me. Is there any other way to solve this problem? Your help is very appreciated. Thanks.

-Abhijit