Untitled

from odoo import models, fields, api

class ResConfigSettings(models.TransientModel):
    _inherit = 'res.config.settings'

    default_discount_percentage = fields.Float(
        string="Default Discount (%)"
    )

    def get_values(self):
        """Carga los valores"""
        res = super().get_values()
        params = self.env['ir.config_parameter'].sudo()
        res.update(
            default_discount_percentage=float(params.get_param('custom_discount_value.default_discount_percentage', default=0.0))
        )
        return res

    def set_values(self):
        """Guarda los valores en ir.config_parameter."""
        super().set_values()
        params = self.env['ir.config_parameter'].sudo()
        params.set_param('custom_discount_value.default_discount_percentage', self.default_discount_percentage)