First we're calculating Average, Median, Min, Mas, for everything that gets graphed, not just Created Virtual Users. I admit that Average and Median and Min doesn't have much value for Created Virtual Users. It's far more valuable for things like Requests/second, but we're being consistent and doing the same calculations for everything that is graphed.
Yes, Max represents the total number of virtual users that were created over the entire life of the test. It's not how many completed, but how many the load agent started up while the test was running.