I've heard through the grapevine that the PowerPoint "word count" counts
punctuation, and it seems to be true. A presentation with the words "This is
a test" (no period) is shown as being 4 words; a presentation with the words
"This is a test." (period after test) is shown as being 5 words. (I tried
this using PPT 2007.)
If anyone knows a way around this, I'd be glad to hear about it!