EBS 12.1.3 - PO approval workflow question

Appropriated any thoughts/ideas about this:

Our business group mentioned they used to have PO approval process in EBS like this:

1. Create a requisition based on a Blanket Purchase Agreement(BPA)

2. the requisition gets auto approved

3. A PO is auto-created based on this req.

4. The PO get auto approved if there is no modifications made for the item lines in the requisition (all item lines picked from BPA without any changes)

5. The PO status should not be auto-approved and status should be 'incomplete' if there is change made to the item lines in the requisition, e.g changes made to Item description or price (item lines in the requisition are different than the ones in BPA)