Power pivot Compare previous record

Hi,

Can you add a manual example showing exactly the output you want to see, please?

All you need to do for that is to add the Sales field again, then right-click it and choose 'Show Values as', then select 'Difference from...' and choose Date as the base field and 'Previous' as the base item.

First note that, date always in date format only (for better calculation) your cell "C12" to "C31" format as "general".
For compare figures you need to add "monthly target" its more dynamic summary.
Data as per your present data record : Refer attach file. In this file refer "Pivot" sheet.
also refer "summary" sheet, in this file
1) customerwise & month/year wise sales calculate (with formula sumifs)
2) Change Customer To Cust
3) Change Month To Month Customerwise
4) Total Sales
5) Average Sales
6) % Month Over Month