Reapproval Process for BPA

Hi there.

We are facing the following scenario:

Someone in the Purchasing Department will create a BPA with 1 line, quantity 100 with a Promised Date - 25.01.2018. The BPA total price is 1000 EUR. The BPA will go through the Approval Process. Once it is approve, it happens that the Purchasing Department modify this BPA. They will split the lines.

• 1 lines with quantitiy 50 and Promised Date 25.01.201. Price 500EUR
• 1lines with quantity 50 and Promised date 15.02.2018.Price 500EUR

The quantity is still the same (100), the BPA Total Price is the same (1000 EUR), but the BPA must go again through the Approval Process. Is there a solution in order the prevent this from happening? Or a way to define a Rule saying. New Document Version with a new position but the same total price, so this new Document Version must not be reapproved?