sale_discount_total/views/sale_order_report.xml

<?xml version="1.0" encoding="utf-8"?>
<openerp>
    <data>
        <template id="report_sale_order_document" inherit_id="sale.report_saleorder_document">

             <!--<xpath expr="//td[@groups='sale.group_discount_per_so_line']/span[@t-filed='l.discount']" position="replace">-->
                 <!--<span t-esc="'%.2f'%(l.discount)"/>-->
             <!--</xpath>-->
             <xpath expr="//span[@t-field='l.discount']" position="replace">
                 <span t-esc="'%.2f'%(l.discount)"/>
             </xpath>
             <xpath expr="//div[@class='col-xs-4 pull-right']/table/tr[2]" position="after">
                    <!--<t t-if="o.discount_rate">-->
                    <tr>
                        <td>Discount</td>
                        <td class="text-right">
                            <span t-field="o.amount_discount" t-field-options='{"widget": "monetary", "display_currency": "o.currency_id"}'/>
                        </td>
                    </tr>
                    <!--</t>-->
             </xpath>
            

            <!--<xpath expr="//div[@class='col-xs-4 pull-right']" position="before">-->
                    <!--<div class="col-xs-4">-->
                        <!--<t t-if="o.discount_rate">-->
                        <!--<table class="table table-condensed">-->
                            <!--<tr class="border-black">-->
                                <!--<td>Discount Type</td>-->
                                <!--<td class="text-right">-->
                                    <!--<span t-field="o.discount_type"/>-->
                                <!--</td>-->
                            <!--</tr>-->
                            <!--<tr>-->
                                <!--<td>Discount Rate</td>-->
                                <!--<td class="text-right">-->
                                    <!--<span t-field="o.discount_rate"/>-->
                                <!--</td>-->
                            <!--</tr>-->
                            <!--<tr class="border-black"></tr>-->
                        <!--</table>-->
                        <!--</t>-->
                    <!--</div>-->
            <!--</xpath>-->
        </template>
    </data>
</openerp>