Re-Order Shipping Options in Checkout

// reorder shipping methods
add_filter( 'woocommerce_package_rates' , 'xa_sort_shipping_services_by_cost', 10, 2 );
function xa_sort_shipping_services_by_cost( $rates, $package ) {
	if ( ! $rates )  return;
	
	$rate_cost = array();
	foreach( $rates as $rate ) {
		$rate_cost[] = $rate->cost;
	}
	
	// using rate_cost, sort rates.
	array_multisort( $rate_cost, SORT_DESC, $rates  );
	
	return $rates;
}