Yes of course their is a way.. BUT I made this in Customer Invoice i think you can use this as a guide for your sale order.. but i will translate it to sale order line . By he way i use this in Openerp v 7

In your .py

class sale_order_line(osv.osv):
     _inherit = 'sale.order.line'
     def _amount_line(self, cr, uid, ids, field_name, arg, context=None):
       tax_obj = self.pool.get('account.tax')
       cur_obj = self.pool.get('res.currency')
       res = {}
      if context is None:
        context = {}
    for line in self.browse(cr, uid, ids, context=context):
        if line.amount_discount:
            price = **Here you will put your code on how will you compute your discount by amount**
            taxes =  **And also here.. because it will be affected based on your code in PRICE**
            res[line.id] = taxes['total']
            if line.invoice_id:
                    cur = line.invoice_id.currency_id
                    res[line.id] = cur_obj.round(cr, uid, cur, res[line.id])  
        else:
        price = line.price_unit * (1 - (line.discount or 0.0) / 100.0)
        taxes = tax_obj.compute_all(cr, uid, line.tax_id, price, line.product_uom_qty, line.product_id, line.order_id.partner_id)
        cur = line.order_id.pricelist_id.currency_id
        res[line.id] = cur_obj.round(cr, uid, cur, taxes['total'])
    return res
 _columns = {

     'amount_discount': fields.float('Discount (Amount)', digits_compute= dp.get_precision('Discount')),    
     'price_subtotal': fields.function(_amount_line, method=True, string='Subtotal', type="float",digits_compute= dp.get_precision('Account'), store=True),   
     'price_unit': fields.float('Unit Price', required=True, digits_compute= dp.get_precision('Product Price')),    
     'discount': fields.float('Discount (%)', digits_compute= dp.get_precision('Discount')),       
            }
 sale_order_line()

In your .xml

<record id="name_you_want" model="ir.ui.view">
        <field name="name">name.you.want</field>
        <field name="model">sale.order</field>
        <field name="inherit_id" ref="sale.view_order_form"/>
        <field name="arch" type="xml">
        <xpath expr="//field[@name='discount']" position="after">
                    <field name ="amount_discount"/>
                    </xpath> 
        </field>
  </record>

I will leave to you how to compute discount by amount.. I know you can do that.. Good luck :D I hope that it will be a big help to you :D

Hi,

My client wanted the same feature. I have implemented 6.1 for him. I would like to show you the image of the sale order form. But I dont have enough karma to upload link or image.

But I have used a module to fulfill his requirement. That requirement seems to be common for US industries. OpenERP is more of Europe Industry Standards

Thanks

Hello

I have developed one module which set a discount on whole sale order and customer invoice with fixed and percentage vise. when your quote will move to invoice that same discount and total will move to the invoice I think this module feature will helps you more.

you can see on : http://www.youtube.com/watch?v=RTRB0xq9Y38&feature=youtu.be

To get the module can contact me: dsouzajoseph199@gmail.com

The best way to solve this, add a new sale.order.line to your sale.order with a product "discount" (Product Type Consumable) and add a negative price.

So you have. MyProduct: 199€ Discount: -10€ Sum: 189€

Hello,

We have developed a module which allow users to apply discount (Fixed Amount, Percentage) on Sales and Customer Invoice.

The module also allow user to display the discount on Sales and Invoice report.

Once you Validate the invoice, the module generate the Journal Entries. You can track the discount on P/L report by creating a separate account for the discount which you just have to configure in the company. This account will be used to post the entries of the discount account.

Hope this module will ease everyone's life.

For now, the module is developed for v7 only and we are on the way to migrate it in v8 and v9 as well.

Download: https://apps.odoo.com/apps/modules/7.0/discount_sale_invoice/

Hi,

Yes, you can do it through Price List