add_filter('woe_get_order_value_inv_no', function ($value, $order) { $order_id = $order->get_id(); // Try plugin meta first $invoice = get_post_meta($order_id, 'gst_order_invoice_no', true); if (!empty($invoice)) { return $invoice; } // Recreate same format as your invoice template $order_data = $order->get_data(); $ts = strtotime($order_data['date_created']); $m = (int) date('n', $ts); $y = (int) date('Y', $ts); $fy_start = ($m >= 4) ? $y : ($y - 1); $fy_end = $fy_start + 1; $fy_label = sprintf('%02d-%02d', $fy_start % 100, $fy_end % 100); // same logic as your template if ($order_data['shipping']['state'] == 'KL') { return 'ASISK/' . $fy_label . '/' . $order_id; } return 'ASOSK/' . $fy_label . '/' . $order_id; }, 10, 2);