Confused...

I am seriously obsessive about backing up my work. My NaNo WIP is currently on my laptop, my work PC (so that I can work on it at lunch-time, never during the working day... Honest.), and a memory stick. Also, whenever I finish a chapter, I copy it into a new Google Document and also into Scrivener, the novel-writing package I have on my laptop. I'll be using this to edit it once I've finished the first draft, as it is much more flexible than Word, which is what I'm using for NaNo.

The Scrivener project stats tells you lots of things on top of just a simple word count, including how many paperback pages you have written, and this is what I've generally checked when I've added a new chapter. I copied in Chapters 17 and 18 this morning, and happened to also notice the word count for the project. In Word, I had reached 37,801, as you can see today in my word counter bar. When I looked at the Scrivener word count it said 37,910! I really don't understand the discrepancy, and am inclined to believe the Word total with the belief that it's better to get to 50,000 then realise I've actually done more when I validate it on the NaNo site than the reverse, but it still makes the scientist in me slightly nervous. Which one is right?! There is a discrete total of words (unless there's something funny going on with hyphenations or contractions) and I want to know what it is! Argh!