Subtotal issue when exported to Excel

Hello, I have a report in BOXI R3. when the user is exporting the report to Excel and try to put filter then the subtotal is not coming.

for example, in the report suppose we have a column Client Name,Spend and column Flag which has Y and N as its value. when there is no filter on the report , the grand total for Spend is coming but when the User put the filter on this report and select only Y,subtotal for Y is not coming.

Is there any way in BO to resolve this problem