Material Cost Control: Inventory, Valuation & Efficiency

Key Concepts and Definitions

1. Material Cost: What It Includes

Material cost is the total expenditure incurred to acquire, store, and use raw materials and components in production. It comprises:

• Purchase cost: Invoice price + freight, insurance, taxes, and duties.
• Storage cost: Warehouse rent, handling, insurance, and obsolescence.
• Usage cost: Scrap, spoilage, and wastage during production.

---

2. Inventory Valuation Methods

How a business values its inventory directly impacts cost of goods sold (COGS) and profitability. Three primary methods are used in Nepal:

Worked Example: FIFO vs. LIFO for a Kathmandu Retail Shop (NPR) Assume Shop Everest sells mobile phone accessories. Its inventory transactions in June 2023:

• June 1: 100 units @ NPR 500/unit (Opening stock).
• June 10: Purchased 50 units @ NPR 550/unit.
• June 20: Sold 80 units.
• June 25: Purchased 30 units @ NPR 600/unit.

Calculate COGS and Ending Inventory under FIFO and LIFO.

Solution Table:

Why This Matters for Nepali Businesses:

• Daraz (e-commerce): Uses FIFO for perishable goods (e.g., groceries) to match physical flow.
• Nepal Pharmaceuticals: Uses Weighted Average for bulk drugs to simplify costing.
• Construction firms (e.g., MEGA): Use LIFO for steel and cement to reduce taxable income during inflation.

---

3. Economic Order Quantity (EOQ) Model

The EOQ model determines the optimal order quantity that minimizes total inventory costs (holding costs + ordering costs).

Formula: $$EOQ=\sqrt{\frac{2DS}{H}}$$ Where:

• $D$ = Annual demand (units).
• $S$ = Ordering cost per purchase order (NPR).
• $H$ = Holding cost per unit per year (NPR).

Worked Example: EOQ for a Kathmandu Electronics Shop

• Annual demand (D): 1,200 mobile phone chargers.
• Ordering cost (S): NPR 500 per order.
• Holding cost (H): NPR 20 per charger per year (includes storage, insurance, and opportunity cost).

Calculation: $$EOQ=\sqrt{\frac{2\times 1,200\times 500}{20}}=\sqrt{60,000}=245\text{ units}$$

Total Cost Analysis:

Real-World Application:

• Pathao (ride-hailing): Uses EOQ-like models to optimize driver dispatch (treating drivers as "inventory" to meet demand).
• NTC (Nepal Telecom): Applies EOQ for network equipment procurement to balance bulk discounts and storage costs.

---

4. ABC Analysis of Inventory

Not all inventory items are equally important. ABC Analysis classifies inventory into three categories based on annual consumption value:

Example for a Kathmandu Furniture Manufacturer:

Why ABC Analysis Matters:

• Daraz: Focuses A-items (e.g., mobile phones, laptops) on fast shipping and C-items (e.g., small accessories) on bulk discounts.
• Nepal Pharmaceuticals: Prioritizes A-items (e.g., insulin, antibiotics) for just-in-time (JIT) delivery to avoid stockouts.

---

5. Just-in-Time (JIT) Inventory System

JIT is a lean inventory strategy where materials arrive just as they are needed in production, reducing holding costs.

Key Features:

• Minimizes inventory holding costs.
• Requires supplier reliability and flexible production.
• Common in automotive (Toyota), electronics (Samsung), and food processing.

Example: Toyota’s JIT in Nepal

• Supplier: Nepal Steel Mills (supplies sheet metal).
• Process: Steel arrives daily for car body production.
• Benefit: No warehouse needed; zero holding cost.

Disadvantages for Nepali Businesses:

• Dependence on suppliers (e.g., power cuts, roadblocks).
• No buffer stock → risk of stockouts (e.g., Kathmandu traffic delays).

---

6. Material Cost Control Techniques

---

In the Real World

1. eSewa (Digital Payments)

   • Idea Used: ABC Analysis for inventory management of server resources.
   • How: Critical servers (A-items) are monitored 24/7, while backup servers (C-items) are ordered in bulk.

2. Khalti (Fintech)

   • Idea Used: EOQ for cash reserves.
   • How: Khalti maintains optimal liquidity (cash + digital balances) to minimize holding costs while ensuring transactions.

3. Nepal Rastra Bank (NRB)

   • Idea Used: FIFO for gold reserves.
   • How: NRB values gold purchases using FIFO to reflect the oldest gold first, ensuring transparency in foreign reserves.

4. Daraz (E-Commerce)

   • Idea Used: JIT for fast-moving items.
   • How: Electronics (e.g., smartphones) are shipped directly from suppliers to customers to avoid warehouse costs.

5. NTC (Telecom Infrastructure)

   • Idea Used: Vendor Analysis for network equipment.
   • How: NTC evaluates Huawei vs. Ericsson based on price, reliability, and after-sales service before bulk orders.

---

Exam Tip

1. Memorize Formulas:

   • EOQ, COGS under FIFO/LIFO/Weighted Average, and Reorder Point (ROP = Lead Time × Daily Usage + Safety Stock).
   • Example: If asked to calculate EOQ for a Kathmandu bakery, ensure you show all steps (including units in NPR).

2. Compare Methods:

   • FIFO vs. LIFO: Draw a T-account showing inventory flow and explain tax impact (LIFO reduces taxable income in inflation).
   • ABC vs. XYZ: Create a table classifying items and justify control policies.

3. Real-World Applications:

   • Link theories to Nepali businesses:
     • Nepal Pharmaceuticals → ABC Analysis for drugs.
     • Daraz → JIT for electronics.
     • NTC → Vendor Analysis for telecom equipment.

4. Diagrams Are Your Friends:

   • Always draw:
     • T-accounts for inventory valuation.
     • Flowcharts for the ordering cycle (e.g., EOQ → Order Placement → Receipt → Usage).
     • Mermaid diagrams for JIT vs. Traditional Inventory.

5. Common Pitfalls:

   • Ignoring holding costs in EOQ → leads to wrong optimal order quantity.
   • Miscounting COGS → always verify FIFO/LIFO calculations with a table.
   • Assuming all businesses use JIT → explain when it’s suitable (Toyota) vs. not (small retailers).

---

Final Worked Example: Comprehensive Problem Scenario: Shop Everest (Kathmandu) sells Nepali carpets. Data for May 2023:

• Opening Inventory: 50 carpets @ NPR 20,000 each.
• May 5: Purchased 30 carpets @ NPR 22,000.
• May 15: Sold 40 carpets.
• May 20: Purchased 20 carpets @ NPR 25,000.
• Holding cost: 10% of average inventory value per month.
• Ordering cost: NPR 1,000 per order.

Questions:

1. Calculate COGS and Ending Inventory under FIFO and LIFO.
2. Determine EOQ if annual demand is 600 carpets.
3. Classify the carpets using ABC Analysis (assume annual value: NPR 1,200,000).

Solution:

1. FIFO/LIFO Calculation:

   • FIFO COGS: (50 × 20,000) + (30 × 22,000) = 1,000,000 + 660,000 = 1,660,000.
   • LIFO COGS: (20 × 25,000) + (20 × 22,000) = 500,000 + 440,000 = 940,000.

2. EOQ: $$EOQ=\sqrt{\frac{2\times 600\times 1,000}{0.10\times 20,000}}=\sqrt{60}\approx 245\text{ carpets}$$

3. ABC Analysis:

   • Annual Value: NPR 1,200,000 → Category A (high-value item).

Exam Answer Structure:

• Step 1: Clearly label FIFO/LIFO tables.
• Step 2: Show EOQ formula with units.
• Step 3: Justify ABC classification with value data.