What do the French abbreviations DA, DET and AOR mean? (appears in the payment instructions section of the contract)

I think abbreviations like this should be international, so they should be English abbreviations.

You can also quote French to say that the common language of international trade is English.

D/A

DET is a period of detention and anti-freedom

As far as I know, AOR has two meanings, namely the area of responsibility.

There is also a maritime insurance: any kind of insurance.