function woocommerce_get_order_item_totals_method($total_rows, $order, $tax_display){
	$total_rows['cart_subtotal']['label'] = 'Total Course cost:';
	if ( $order->get_total_discount() > 0 ) {
		$total_rows['discount']['label'] = 'Remaining Balance:';
	}
	if ( $order->get_shipping_total() ) {
		$total_rows['shipping']['label'] = 'Shipping Total:';
	}
    return $total_rows;
}
add_filter('woocommerce_get_order_item_totals', 'woocommerce_get_order_item_totals_method', 10, 3);