The problem becomes one of definition as there really is no standard.
To a 'racer' a 'pack' is typically one qual or main run, typically 5-8 minutes, depending on class. So with a typical race day of 3 quals and a main, that could be stated as 4 packs, or 1 race day. Racers of most any discipline rarely run to low voltage cut off, even in practice runs.
To a 'basher' a 'pack' typically means running the battery until low voltage cut off, which can be anywhere between 10-45 mintues, depending on equipment and useage.
Feel free to define your own terms and useage!