Hello,
In Odoo Studio : 
In the sale module, I created a "commission%" field to set a default value throughout the sale.
In each article line, I created a "com%" field. I would like the default value field "com%" to be the field "comisiion%".
But I want to be able to also modify the "com%" field on 1 line if necessary

screenshot : http://nas.cip-sa.be/temp/comission.jpg
Thank you for your help