I just clicked the 'delete' button on a post that already had 2 votes to delete. A notification box popped up saying:
Vote to delete this post? (21 votes remaining)
I clicked on 'OK' and the post was promptly deleted, having garnered only 3 delete votes.
This has happened many times before: the number of votes listed as remaining is always much larger than the actual number of votes actually required for it to be deleted. IME, 3 votes from Trusted Users is enough to delete a question, but the notification always says 20 or 21. Looks like a bug to me.