I'm afraid that it can happen that the word count can slightly defer in the statistics. This is basically because Diarium counts the words in the statistics by splitting the html text while the word count in the details page is splitting the formatted text (not html). E.g. this would be html:
<p>A</p><p>B</p>
No space, so it would output as 1 word.
But it would render as this:
A
B
So 2 words
I think it's not a big problem (and it also hasn't been noticed by users in the past), so I currently don't plan to invest time in order to adjust this