Dropship Sales orders Split Lines Unable to update the PO Price.

Summary: Dropship Sales orders Split Lines Unable to update the PO Price. 

Dropship sales Order Sales Order Split lines unable to update the PO price.
Using service Mapping for SO Line Extension for PO Price information to purchase Requisition and Purchase orders new price not able to update.

Ex: Sales order line-01 Qty 10 split into 6 and 4 quantity, PO Price 150 purchase requisition and
PO created, SO Lines 1.1 Line status "Awaiting Billing", 1.2 Line status "Awaiting Shipping.

 SO Line 1.2  4 Quantity PO new price 160 update in Sales Order EFF, it is not updated in PR and PO.

could you please provide the solution, how to update the remaining quantity PO New Price.