Imho it all depends on how much you value your time. Calculate the number of hours it will take you to cook the 32 butts. Take the number of hours times your labor cost (per hour). Add in any incidental costs such as wood, rub, injection, delivery expenses (total of these times 3 for margin purposes).
i.e. You can cook all 32 butts in one run in 14 hours. Your time is worth $40/hr. Your incidental costs total $100 ($300 charged after margin added, $100 x 3). Labor of 14hrs x $40/hr = $560, Incidentals $300, Total Charge = $860 (personally I would round that up to an even grand)
Of course if you have to do multiple runs to cook the 32 butts the cost will increase by the number of runs times your labor costs. The folks that quoted him the $2K could easily have been experiencing just this scenario. They may need to make two runs due to the capacity limits of their equipment which would then virtually double their labor cost.
CAVEAT: IF we cooked "other peoples meat" this is how we would charge it out. However, due to quality control practices, on our part, we do not take on these types of jobs. But that is a whole other Thread.