function get_order_total( $order_data, $order ) {

    $order_data['tax_amount']      = $order->get_total_tax();
    $order_data['coupon_discount'] = $order->get_total_discount();

    return $order_data;

}

add_filter( 'wpf_woocommerce_customer_data', 'get_order_total', 10, 2 );