Monthly Report to find duplicates and update

[mikyas]

I need a formula to find and update all the duplicate entries below the original entries in the Detailed Report Sheet as shown in the picture below. I have monthly sales which is a repeating items and at end of the month I need to populate 1 single report which can show in the first duplicate item the Purchase+onHand-Sales and the rest duplicate items to show 0 as value.
Only the first item will be update with the purchase and on hand for each duplicate.

Please help me URGENTLY.

 

[sandy666]

use XL2BB to post your representative source data AND expected result