Hi... a quick improvement you can make to your plugin is to make sure that Custom Post Types can be included in the counts as well.
You can do this pretty quickly in the
most_shared_posts_update_social_data function, by adding the
post_type => any argument to your query, like this:
$args = array(
'posts_per_page' => 500,
'orderby' => 'date',
'order' => 'DESC',
'ignore_sticky_posts' => 1,
'post_type' => 'any'