I don't know the version, but in your button click you can add some custom code like in V13,

for line in self.move_line_ids:

    line._onchange_price_subtotal()

Hello Abdalmola Mustapha,

Sorry i don't understood your answer.

Could you explain differently or share an example please.

Vincent

in line automatic calculate but if only if customize in method calculate  to stop auto discount
after that using your method to calculate discount