First and foremost - Great job on the miles.

As for the rule of thumb that I use along with most of my riding buddies, it counts as a century if you do not go to seep between the sets of the ride.

So, if you ride 80, take a 2 hour break and ride another 20, you have a century.

If you ride 80, sleep for the night and ride another 20, you dont have a century.

Sounds like you still had a heck of a great run though.

Holly