Just to be clear, what bobert24 and I were talking about (I think) has nothing to do with trying to figure out how the closing date is determined. Of course it's determined before you ever use the card. That's of no concern for me and I agree is pretty much set randomly (maybe this is set by a Citi internal cash flow algorithm?)
What I'm interested in looking at is seeing if we can figure if there is a specific (or more likely) set of circumstances in which the annual fee does not post on first statement.