AutoCal holds enough license spaces to tune up to 8 controllers. The first license is installed on the unit before it is despatched, additional licenses can be purchased as needed.
The only catch is ONLY the first FlashScan V2 that the AutoCal is linked to can supply tunes to the AutoCal, so you can't switch tuners, or purchase tunes for vehicle A from 1 tuner and tunes for vehicle 2 from a second tuner
You could, but to add tunes to it, it needs to be connected physically to a FlashScan device to marry the 2, so unless you had your own FlashScan, you'd need to send it to someone for that process to take place