Ferrous Material GR at rate different from PO rate.

Dear All,

I have scenario as below.

Our client procuring ferrous material. the rate is based on Chromium %.

Current situation is that if Cr % is between 57 - 63 the rate is 100 Rs / kg. on 60 % prorata basis.

Purchase Order will be generated with rate 100 Rs./Kg for required quantity.

Ie. if GR receipt with Cr % 61, then the rate of Material will be 101.66 Rs./Kg. (61/60*100)

if GR receipt with Cr % 59, then the rate of Material will be 99.33 Rs. Kg. (59/60*100)

How to Map this in SAP.

Prashant Salvi.