$inv->tax_included = $cart->tax_included;
$supp = get_supplier($cart->supplier_id);
$inv->tax_group_id = $supp['tax_group_id'];
-// $inv->ov_discount 'this isn't used at all'
+
$inv->ov_amount = $inv->ov_gst = $inv->ov_discount = 0;
foreach($cart->line_items as $key => $line) {