With the filter you can integrate new separators for the CSV export. By default Excel uses , and ;. However, if you need a plus or a other separator, you can extend the list this way.

Place this code in your functions.php to add a plus to the separators:

<?php
/**
 * Inserts a new separator for the CSV.
 * 
 * @param array $separators
 *
 * @return array
 */
add_filter( 'helpful_export_separators', function( $separators ) {
	$separators[] = '+';
	return $separators;
});