Discounted PO receipts should not affect the Average price of item

Hi All

We are following average costing method in inventory.

We have receipts in inventory for PO.

Price is updated with respects to new receipts.

But when the Item Price is discounted, It also affected the price of item

Everything is working fine according to oracle seeded functionality.

As a example below, user requirement is to have price to remain 2 only.

       

Dates	Qt Rcv in inventory	Unit Price recipt of item	Line Price	Avg Price calculation  in oracle	Current Avg price	Customer expected Avg price
1-Jan-16	2000	2	4000	4000/2000	2	2
10-Jan-16	2000	0 (DISCOUNTED)	0	4000/4000	1	2

We don't want to consider the price discounted  in the inventory.

Is there a way to mitigate the affect of discounted prices  for  item which we receive from supplier.