MC Qu. 74 Differential Chemical produced... Differential Chemical produced 12,000 gallons of Preon and 16,000 gallons of Preon. Joint costs incurred in producing the two products totaled $8,500. At the split-off point, Preon has a market value of $6.00 per gallon and Preon $3.00 per gallon. Compute the portion of the joint costs to be allocated to Preon if the value basis is used.