16.3 Relevant Costing & Short-Term Tactical Decisions

Relevant Costing & Short-Term Tactical Decisions

Short-term tactical decision making requires management accountants to identify, assemble, and analyze relevant data to choose among competing operational alternatives. Unlike external financial reporting governed by Philippine Financial Reporting Standards (PFRS), which mandates full absorption costing and historical cost matching, internal decision analysis relies on relevant costing (differential analysis). On the CPALE, mastering relevant costing ensures candidates can quickly cut through irrelevant data clutter and evaluate the true incremental profit impact of operational choices.

---

1. Principles of Relevance in Managerial Decisions

For a financial item to be classified as relevant to a business decision, it must simultaneously satisfy two indispensable criteria:

1. Future-Oriented: The cost or revenue must be an expected future cash flow or outlay.
2. Differential (Incremental): The cost or revenue must differ among the alternatives under consideration.

                               Criteria for Cost Relevance
                                            │
               ┌────────────────────────────┴────────────────────────────┐
               ▼                                                         ▼
     Is it an expected future cash flow?                    Does it differ among alternatives?
               │                                                         │
        NO ────┼────► IRRELEVANT (Sunk Cost)              NO ────┼────► IRRELEVANT (Unavoidable)
               │                                                         │
              YES                                                       YES
               │                                                         │
               └────────────────────────────┬────────────────────────────┘
                                            ▼
                               RELEVANT COST / REVENUE

Categories of Irrelevant Costs

• Sunk Costs: Costs that have already been incurred and cannot be avoided or altered by any present or future decision. Examples include historical acquisition costs of machinery, accumulated depreciation, past book values, and previously incurred research and development outlays.
• Future Costs that Do Not Differ: Expected future expenditures that will be incurred regardless of which alternative is chosen (e.g., general factory rent, property insurance under an existing non-cancellable plant lease).
• Allocated Common Fixed Costs: Arbitrary prorations of enterprise-wide executive salaries, central IT, or corporate legal overhead that will persist in total whether a division or product line is retained or terminated.

Opportunity Costs

An opportunity cost represents the maximum net contribution or benefit forgone by selecting one course of action over the next best alternative. Although opportunity costs are never recognized in the general ledger or reported on PFRS financial statements (as they do not represent actual historical outlays), they are critically relevant in management accounting whenever facilities, labor, or funds operate at or near full capacity.

Qualitative Factors

Quantitative analysis must be complemented by qualitative considerations:

• Employee Morale: Plant closures or component outsourcing may trigger layoffs and union friction.
• Product Quality & Reliability: External vendors may compromise manufacturing tolerances or delivery schedules.
• Customer Relations & Brand Perception: Discontinuing a product line may alienate loyal corporate clients who expect a comprehensive product suite.
• Supplier Dependency: Outsourcing a core component gives external suppliers future pricing leverage.

---

2. Tactical Decision Model 1: Make or Buy (Outsourcing Decisions)

In a make-or-buy decision, management evaluates whether to manufacture an assembly component internally or purchase it from an external supplier.

Relevant Decision Framework

• Relevant Costs to Make: Direct materials, direct labor, variable factory overhead, traceable avoidable fixed overhead (e.g., specialized tooling rentals, supervisory salaries that would be eliminated), plus the opportunity cost of released production capacity.
• Relevant Costs to Buy: The purchase price quoted by the external supplier, incoming freight, receiving and inspection costs, and contract administration.
• Irrelevant Costs: Unavoidable general fixed overhead that will continue regardless of the decision.

Worked Example: Make or Buy with Opportunity Cost

Scenario: Cebu Electronics Inc. currently manufactures $20{,}000\text{ units}$ of a subassembly (Component X-40) annually. The per-unit absorption cost to manufacture is:

• Direct materials: $\text{PHP }45$
• Direct labor: $\text{PHP }30$
• Variable factory overhead: $\text{PHP }15$
• Fixed factory overhead (allocated): $\text{PHP }35$ (Total absorption cost: $\text{PHP }125$)

An external vendor offers to supply $20{,}000\text{ units}$ of Component X-40 at a delivered price of $\text{PHP }105\text{ per unit}$. Analysis reveals that of the $\text{PHP }35$ fixed overhead, $\text{PHP }10$ is direct supervisor salary that can be eliminated if the component is outsourced, while the remaining $\text{PHP }25$ represents allocated plant depreciation and general factory insurance that will persist. Furthermore, if Component X-40 is outsourced, the freed manufacturing floor space can be rented to a neighboring business for $\text{PHP }180{,}000\text{ per year}$.

                               Differential Cost Analysis: Make vs Buy
                                          (20,000 Units)
----------------------------------------------------------------------------------------
Cost Element                         Make (PHP)            Buy (PHP)      Differential
----------------------------------------------------------------------------------------
Purchase Price (20,000 * PHP 105)             0            2,100,000      + 2,100,000
Direct Materials (20,000 * PHP 45)      900,000                    0        - 900,000
Direct Labor (20,000 * PHP 30)          600,000                    0        - 600,000
Variable Overhead (20,000 * PHP 15)     300,000                    0        - 300,000
Avoidable Fixed Overhead (20,000 * 10)  200,000                    0        - 200,000
Unavoidable Fixed Overhead (20,000 * 25) 500,000            500,000                0
Opportunity Cost (Rental Income Foregone) 180,000                  0        - 180,000
----------------------------------------------------------------------------------------
Total Relevant Cost                 PHP 2,180,000        PHP 2,100,000    - PHP 80,000
----------------------------------------------------------------------------------------

Decision: Buy from the external supplier. Outsourcing yields a net financial advantage of PHP 80,000 annually. Note that the $\text{PHP }500{,}000$ unavoidable fixed overhead is identical under both alternatives and is properly excluded from the differential advantage.

---

3. Tactical Decision Model 2: Accept or Reject a Special Order

A special order represents a one-time request for a batch of goods at a discounted selling price outside regular distribution channels.

Analytical Decision Rules

1. When Operating with Excess (Idle) Capacity:
   • Existing fixed overhead will be incurred regardless and is irrelevant.
   • Only incremental variable manufacturing costs, special tooling/setup costs, and order-specific distribution expenses are relevant.
   • Decision Rule: Accept if: $\text{Special Order Price} > \text{Incremental Variable Cost per Unit}$.
2. When Operating at Full Capacity:
   • Producing the special order requires displacing regular sales units.
   • Opportunity Cost: Lost contribution margin from regular sales sacrificed.
   • Decision Rule: Accept if: $\text{Special Price} \ge \text{Incremental Variable Cost} + \text{Lost Regular Contribution Margin per Unit}$

Worked Example: Special Order under Full vs Excess Capacity

Scenario: Davao Furniture Corp. produces ergonomic office chairs selling regularly for $\text{PHP }2{,}500\text{ each}$. Unit variable costs are $\text{PHP }1{,}400$ (manufacturing $\text{PHP }1{,}200$, sales commission $\text{PHP }200$), and fixed manufacturing overhead is $\text{PHP }500\text{ per unit}$ based on normal capacity of $10{,}000\text{ chairs}$. A foreign corporation offers to purchase $1{,}500\text{ chairs}$ at a special price of $\text{PHP }1{,}600\text{ each}$. The special order requires additional customized branding costing $\text{PHP }100\text{ per chair}$, but incurs no regular sales commission.

• Case A: Excess Capacity Exists (Current production = 8,000 chairs):
  • Incremental Revenue: $\text{PHP }1{,}600$
  • Incremental Cost: Variable manufacturing ($\text{PHP }1{,}200$) $+$ Custom branding ($\text{PHP }100$) $= \text{PHP }1{,}300$
  • Net Incremental Gain per Chair: $\text{PHP }1{,}600 - \text{PHP }1{,}300 = \text{PHP }300$
  • Total Profit Impact: $1{,}500 \times \text{PHP }300 = +\text{PHP }450{,}000$. Accept the special order.
• Case B: Full Capacity (Current production = 10,000 chairs; 1,500 regular chairs displaced):
  • Lost regular contribution margin per chair: $\text{PHP }2{,}500 - \text{PHP }1{,}400 = \text{PHP }1{,}100$
  • Minimum Acceptable Price: $\text{Incremental Cost } (\text{PHP }1{,}300) + \text{Lost Regular CM } (\text{PHP }1{,}100) = \text{PHP }2{,}400$
  • At $\text{PHP }1{,}600$, the company suffers a net loss of $\text{PHP }800\text{ per chair}$ ($1{,}500 \times \text{PHP }800 = -\text{PHP }1{,}200{,}000$). Reject the special order.

---

4. Tactical Decision Model 3: Drop or Keep a Segment or Product Line

When a product line, department, or business territory reports an operating loss on standard absorption financial reports, executive management may be tempted to eliminate it. Relevant costing requires evaluating the Segment Margin.

The Segment Margin Hierarchy

$\text{Sales Revenue} - \text{Variable Expenses} = \text{Contribution Margin}$

$\text{Contribution Margin} - \text{Traceable Avoidable Fixed Costs} = \text{Segment Margin}$

$\text{Segment Margin} - \text{Common Allocated Fixed Costs} = \text{Net Operating Income (Loss)}$

• Traceable (Direct) Fixed Costs: Costs directly caused by the segment that disappear if the segment is eliminated (e.g., segment advertising, store rent, equipment lease).
• Common (Indirect) Fixed Costs: Enterprise costs supporting multiple segments that will not change in total if one segment is dropped (e.g., company headquarters rent, president's salary).
• The Golden Rule: An entity should keep any segment that generates a positive Segment Margin ($\text{Segment Margin} > 0$), because that positive margin contributes toward absorbing common fixed costs. Dropping it would reallocate the common fixed costs across remaining segments and decrease total company operating profit by the amount of the lost segment margin.

Worked Example: Segment Retention Analysis

Scenario: Iloilo Trading Company operates three product lines with the following annual results:

Management wants to drop Product Line Gamma because of its $\text{PHP }20{,}000$ operating loss.

• If Gamma is dropped, its $\text{PHP }150{,}000$ contribution margin is lost, and $\text{PHP }90{,}000$ of traceable fixed costs are saved.
• Net loss in operating profit: $\text{Lost Segment Margin} = \text{PHP }60{,}000$.
• The $\text{PHP }80{,}000$ common fixed cost will simply be reallocated to Alpha and Beta, reducing total enterprise profit from $\text{PHP }200{,}000$ down to $\text{PHP }140{,}000$.
• Decision: Retain Product Line Gamma.

---

5. Tactical Decision Model 4: Sell as Is or Process Further (Joint Products)

In joint manufacturing operations (e.g., petroleum refining, meat processing, chemical synthesis), multiple distinct products emerge simultaneously from a common input at the split-off point.

The Sunk Joint Cost Fallacy

• Joint Production Costs incurred up to the split-off point are past, sunk expenditures that cannot be altered by subsequent processing decisions. Any allocation of joint costs (via physical measure, sales value at split-off, or net realizable value) is strictly for inventory valuation and completely irrelevant to the sell-or-process-further decision.
• Decision Rule: Process a joint product beyond the split-off point if and only if: $\text{Incremental Revenue from Further Processing} > \text{Incremental Processing Cost}$ $\text{Incremental Revenue} = \text{Final Sales Value after Processing} - \text{Sales Value at Split-off}$

Worked Example: Chemical Joint Processing

Scenario: ChemLab Philippines processes raw chemicals incurring joint processing costs of $\text{PHP }1{,}200{,}000$ up to the split-off point, where 10,000 liters of Product X and 5,000 liters of Product Y emerge:

• Analysis for Product X:
  • Incremental Revenue: $\text{PHP }200 - \text{PHP }150 = \text{PHP }50\text{ per liter}$
  • Incremental Cost: $\text{PHP }40\text{ per liter}$
  • Incremental Gain: $\text{PHP }50 - \text{PHP }40 = +\text{PHP }10\text{ per liter} \times 10{,}000\text{ L} = +\text{PHP }100{,}000$.
  • Decision for X: Process further into final chemical.
• Analysis for Product Y:
  • Incremental Revenue: $\text{PHP }130 - \text{PHP }80 = \text{PHP }50\text{ per liter}$
  • Incremental Cost: $\text{PHP }55\text{ per liter}$
  • Incremental Loss: $\text{PHP }50 - \text{PHP }55 = -\text{PHP }5\text{ per liter} \times 5{,}000\text{ L} = -\text{PHP }25{,}000$.
  • Decision for Y: Sell at split-off point.

---

6. Tactical Decision Model 5: Product Mix under Capacity Constraints

When customer demand exceeds production capacity, a business faces a bottleneck or limiting constraint (e.g., machine hours, skilled direct labor hours, raw material supply). Under capacity restrictions, the product with the highest unit contribution margin or highest contribution margin ratio is not necessarily the most profitable.

The Optimization Rule

Total enterprise operating profit is maximized by prioritizing the product that generates the highest Contribution Margin per Unit of the Constrained Resource:

$\text{CM per Constrained Resource Unit} = \frac{\text{Unit Selling Price} - \text{Unit Variable Cost}}{\text{Constrained Resource Required per Unit}}$

Worked Example: Allocating Machine Hours

Scenario: Pampanga Precision Engineering manufactures two precision components utilizing a specialized computer-numeric-control (CNC) milling machine. Total available machine capacity is $6{,}000\text{ hours}$ per month.

Evaluation:

• While Component Deluxe yields a higher unit contribution margin ($\text{PHP }300$ vs $\text{PHP }180$), we must compute the return per machine hour: $\text{CM per Machine Hour (Standard)} = \frac{\text{PHP }180}{1.5\text{ hours}} = \text{PHP }120\text{ per hour}$ $\text{CM per Machine Hour (Deluxe)} = \frac{\text{PHP }300}{3.0\text{ hours}} = \text{PHP }100\text{ per hour}$
• Ranking: Component Standard is ranked First; Component Deluxe is ranked Second.
• Optimal Production Schedule:
  1. Satisfy maximum demand for Component Standard: $3{,}000\text{ units} \times 1.5\text{ hours} = 4{,}500\text{ machine hours}$
  2. Allocate remaining hours to Component Deluxe: $\text{Remaining Hours} = 6{,}000 - 4{,}500 = 1{,}500\text{ machine hours}$ $\text{Deluxe Units to Produce} = \frac{1{,}500\text{ hours}}{3.0\text{ hours/unit}} = 500\text{ units}$
• Total Contribution Margin Generated: $(3{,}000 \times \text{PHP }180) + (500 \times \text{PHP }300) = \text{PHP }540{,}000 + \text{PHP }150{,}000 = \text{PHP }690{,}000$