Approval of PO with negative lines

Summary:

Since version 23A it is possible to create PO lines with negative value. In this context, I have an interesting problem with the approval of such POs:

Let's assume that PO approval is based on the order amount and purchase orders over $100,000 must be approved by the CFO.

A user creates a PO with two lines. The first line with amount $1,000,000 and a second line with a negative amount - $999,999. The total amount of the order is then $1 and therefore does not require CFO approval.

Once the order is approved, the user can simply manually close the negative amount line without matching to the credit memo. The first line of $1,000,000 can then be invoiced and paid event though this amount was not approved by CFO.