Hello,
I'm Alexandre, a senior data analyst living in France, I’m usually working on development/coding projects, but as a French native i can help you on this !
I have downloaded your examples, if I understed it right, you want to get all the Unit Price / Total / Discount / Grand total from every files you want ? I can achieve that for you :)
I can build you an Excel tool that will allow you to select multiple files, and get all the data you need from it.
Feel free to contact me so we can discuss it !
Best regards,
Alex.