But how will the car access this server with no data connection? You are able to perform a completely Offline Update using a USB or SD card with the update on it. Online Update is an option but not the only one.
When you update via the vehicle data connection the server side counter records this. If you choose to download and create a USB / SD card via myAudi then said creation communicates with the server side in order to update the counter, even if you don't apply the update.
But there are people who claim that they share a USB drive between cars and the updates work as long as they are within 5 versions. So an account that has not downloaded any map update and that car has only used 'other' USB, and yet is able to determine that its had its quota of 5 updates. How is that done?