flectra/addons/account_discount/report/custom_invoice_report.xml

<?xml version="1.0" encoding="utf-8"?>
<flectra>
    <template id="custom_invoice_report_layout" inherit_id="account.report_invoice_document">
        <xpath expr="//div/div[hasclass('clearfix')]" position="replace">
            <div class="clearfix">
                <div id="total" class="row">
                    <div class="col-xs-5 pull-right">
                        <table class="table table-condensed" style="min-width: 250px;max-width: 400px;">
                            <tr>
                                <td><strong>Gross Amount</strong></td>
                                <td class="text-right">
                                    <span t-field="o.gross_amount" t-options='{"widget": "monetary", "display_currency": o.currency_id}'/>
                                </td>
                            </tr>
                            <tr>
                                <td><strong>Discount</strong></td>
                                <td class="text-right">
                                    <span t-field="o.discount" t-options='{"widget": "monetary", "display_currency": o.currency_id}'/>
                                </td>
                            </tr>
                            <tr class="border-black" style="border-bottom:1px solid #dddddd;">
                                <td><strong>Subtotal</strong></td>
                                <td class="text-right">
                                    <span t-field="o.amount_untaxed" t-options='{"widget": "monetary", "display_currency": o.currency_id}'/>
                                </td>
                            </tr>
                            <t t-foreach="o._get_tax_amount_by_group()" t-as="amount_by_group">
                                <tr style="border-bottom:1px solid #dddddd;">
                                    <t t-if="len(o.tax_line_ids) == 1 and o.amount_untaxed == amount_by_group[2]">
                                        <td><span t-esc="amount_by_group[0]"/></td>
                                        <td class="text-right">
                                            <span t-esc="amount_by_group[3]"/>
                                        </td>
                                    </t>
                                    <t t-else="">
                                        <td>
                                            <span t-esc="amount_by_group[0]"/>
                                            <span>&amp;nbsp;<span>on</span>
                                                <t t-esc="amount_by_group[4]"/>
                                            </span>
                                        </td>
                                        <td class="text-right">
                                            <span t-esc="amount_by_group[3]" />
                                        </td>
                                    </t>
                                </tr>
                            </t>
                            <tr class="border-black">
                                <td><strong>Total</strong></td>
                                <td class="text-right">
                                    <span t-field="o.amount_total" t-options='{"widget": "monetary", "display_currency": o.currency_id}'/>
                                </td>
                            </tr>
                        </table>
                    </div>
                </div>
            </div>
        </xpath>
    </template>
</flectra>