ACX5903 Chap.9 Full Costing
Full Costing
The official schedule places full costing in Week 9. This chapter defines the cost object, distinguishes traceable and shared resources, selects drivers that reflect consumption and separates long-run full-cost questions from short-run relevant-cost decisions.
A cost cannot be called direct or indirect until the cost object is named. The object may be a product, service, job, customer, channel or department.
A resource traceable to one department may still be shared across the products made there. Define the object and decision horizon first, then ask whether the resource can be economically traced to it. This prevents a classification from being treated as an inherent property of the expense.
Direct resources are traced using observable consumption.
Indirect resources require an allocation process: collect related overhead in an appropriate pool, select a driver, calculate the assignment basis and apply it consistently. A credible driver represents the activity that consumes the pool. Labour time, machine use, purchase orders or support transactions may suit different resources.
Convenience is not enough if the chosen basis systematically transfers cost between simple and complex work.
Evaluate the result as well as the mechanics. Ask whether the cost pool is internally coherent, whether the driver changes with resource consumption, and whether unusual products receive a plausible share.
A full cost can support long-run pricing, capacity planning and resource accountability, yet it contains allocation judgement. Sensitivity to a different defensible driver reveals how much of a reported product margin comes from operations and how much comes from the assignment rule.
Keep purpose visible.
Full cost asks what total resources support an object over a sustained horizon; relevant cost asks what future amounts change between alternatives. An allocated shared amount may matter for long-run recovery even when it is not avoidable in an immediate decision.
The available unit materials identifies Week 9 but lacks the detailed later lecture deck, so confirm course-specific mechanics in current class material and use this chapter's traceability and driver tests to explain the reasoning.
What this chapter covers
- 01
Cost object definition
- 02
Direct resource tracing
- 03
Indirect resource assignment
- 04
Allocation driver choice
- 05
Cost distortion
- 06
Long-run and short-run use
Worked example · free
Choose an allocation driver
- +2Define the cost objects as routine and customised tests, then distinguish direct resources from shared support.
- +2Explain that technician hours miss setup and review consumption and can underassign cost to customised work.
- +2Separate support pools and use setup counts and review time where those drivers justify their measurement cost.
Key terms
- Full cost
- Full cost includes direct resources and an assigned share of indirect resources associated with a cost object.
- Direct cost
- A direct cost can be traced to the specified cost object without arbitrary allocation.
- Indirect cost
- An indirect cost supports multiple cost objects and requires an assignment rule or driver.
- Allocation driver
- An allocation driver is a measurable factor used to assign shared resource cost according to expected consumption.
- Cost distortion
- Cost distortion occurs when the assignment method overstates one object's resource use and understates another's.
Full Costing FAQ
How can an allocation be checked?
Reconcile the total amount assigned to cost objects with the resource pool, then inspect whether the driver represents consumption. A numerical reconciliation catches missing cost but cannot prove the driver is fair. Compare a second defensible driver and explain which objects move, why they move and which decision the resulting full cost supports.
Why must the cost object be defined first?
Traceability depends on what is being measured. A supervisor can be direct to a department but indirect to each product, so classification without an explicit object can change meaning mid-answer.
Is a more detailed allocation always better?
No. Additional pools and drivers can improve representation but require data, maintenance and explanation. The design should prevent decision-changing distortion without creating measurement cost that exceeds the benefit.
How does full cost differ from relevant cost?
Full cost associates total direct and indirect resources with an object, often for longer-run planning and pricing. Relevant cost isolates future differences between alternatives for a specific decision.
Exam move
Take a service or product and define three possible cost objects at different levels. Reclassify the same resources for each object to see how traceability changes. For every driver, write the consumption relationship and one likely distortion. End by stating whether the decision needs full cost or only changing future effects.
Construct two overhead pools with different consumption patterns and reject any driver selected merely because it is easy to obtain. Reassign the same pool with a second defensible driver and explain which products gain or lose cost. Then separate the long-run resource-recovery question from an immediate avoidability question.
Verify the specific Week 9 calculation sequence against current class material because the available unit materials does not contain that later lecture deck.
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