I wouldn't be surprised if the final zero is actually intentional; it would allow incrementing it if you need to publish more than one version on the same date. It's not likely to be needed, but if something is on fire and you absolutely need to push out a quick fix, having to figure out what version to call it is probably the last thing you want to have to worry about.
Never attribute to some deeply sophisticated planned ahead engineering, that which can be satisfactorily explained by the fact that it's a lot easier to serialize and deserialize a System.Version in an HTTP body, in a universal fashion that will work for every computer in whatever locale, than it is a System.DateTime plus a separate sequence number. (-:
