Change Order functionality - Buyer adding new line on change order for REQ-PO Case

Summary

Buyer adding new line on Change Order

Content

Hi All

I have scenario where Business process says every Purchase order is backed by Requisition and it mean they should not create PO without any Requisition. Procurement Requester cannot ADD NEW Line on Change Order; he can only modify the existing line. So in this Req-PO case if Buyer is adding new line on the Change Order; is it correct functionality/Process and isn't any Audit issue? 

Below steps for understanding -

1. Query the Requisition/ Click on Requisition link Req#PR1234 > Actions - Edit Order
2. Then this will open Edit Change Order page > Go to Lines > Actions – Add Row