Net price from valuation Type

Hi all,

I'm facing trouble in purchase order sap mm. From standard SAP, Net Price adopted from Info Record / Last Po.

But, my client want adopt net price per valuation type not from info record sap.

and also if there any new price from PO, my client only want change in Purchase Order not from the others.

Is there any solutions from me ?

Thank you

Regards,

Raymond