Calculations in PivotTable

Hi Everyone!

I have a pivot-table and i want to do some custom calculation on the existing data.

I have done this through formulas highlighted in yellow, Is there a way where I can integrate in pivot table.
I have tried doing a calculated field, but it doesn't seem to work as the underlying data is not a number, but a date.

Thanks.

If you will add two additional columns to the raw data - one which is 1 for each row and 1 which is 1 for items with call date, then you may create calculated field dividing one by the other.