Hi!
Well, not without a modification to the code. The ordering always uses relevance, then date descending.
If you want to change that, just follow these steps:
1. Open up the wp-content\plugins\related-posts-pro\includes\related_content.class.php file on your server via FTP.
2. Find line 577 which should be this:
[php]ORDER BY relevance DESC, " . $wpdb->posts . ".post_date DESC[/php]
3. Change that to:
[php]ORDER BY " . $wpdb->posts . ".post_date ASC[/php]
..or, if you still want relevance as primary, but date ascending you can also try:
[php]ORDER BY relevance DESC, " . $wpdb->posts . ".post_date ASC[/php]
4. After the change, save the plugin options, so the cache is cleared.
This should very likely do the trick.