[Plugin: Post Word Count] How to just count the words in a single post

The plugin (and code within it) suggests that using the shortcode will only return the wordcount for that post if you’re viewing a single post, however I get the total word count on both index.php and single.php.

Is this because I’m using 2.7? Is there any tweaks I can do to make it work on single posts?

https://www.ads-software.com/extend/plugins/post-word-count/