8-5: Beware of Unit Costs, Costs Beyond the Split-off Point are not Necessarily all
Variable
Table 8-12 in the text allocates joint costs using net realizable value as the allocation base.
What critical assumptions underlie the analysis in Table 8-12? That is, under what circumstances
can the data in this table be used to assess product line profitability?
8–5: Solution to Beware of Unit Costs, Costs Beyond the Split-off Point are not Necessarily
all Variable (20 minutes)
8-6: Allocating joint costs
Sonimad Sawmill manufactures two lumber products from a joint milling process. The
two products developed are mine support braces (MSBs) and unseasoned commercial building
lumber (CBL). A standard production run incurs joint costs of $300,000 and results in 60,000
units of MSB and 90,000 units of CBL. Each unprocessed unit of MSB sells for $2 per unit and
each unprocessed unit of CBL sells for $4 per unit.
If the CBL is processed further at a cost of $200,000, it can be sold at $10 per unit but
10,000 units are unavoidably lost (with no discernible value). The MSB units can be coated with
a preservative at a cost of $100,000 per production run and then sold for $3.50 each.
Required:
a. If no further work is done after the initial milling process, calculate the cost of CBL using
physical quantities to allocate the joint cost.