Decorative Doors, Inc., produces two types of doors, interior, and exterior. The company's simple costing system has two direct-cost categories (materials and labor) and one indirect-cost pool. The simple costing system allocates indirect costs on the basis of machine-hours. Recently, the owners of Decorative Doors have been concerned about a decline in the market share for their interior doors, usually their biggest seller. Information related to Decorative Doors production for the most recent year follows:

Interior Exterior
Units sold 3,200 1,800
Selling price $125 $200
Direct material cost per unit $30 $45
Direct manufacturing labor cost per hour $16 $16
Direct manufacturing labor-hours per unit 1.50 2.25
Production runs 40 85
Material moves 72 168
Machine setups 45 155
Machine-hours 5,500 4,500
Number of inspections 250 150

The owners have heard of other companies in the industry that are now using an activity-based costing system and are curious how an ABC system would affect their product costing decisions. After analyzing the indirect-cost pool for Decorative Doors, the owners identify six activities as generating indirect costs: production scheduling, material handling, machine setup, assembly, inspection, and marketing. Decorative Doors collected the following data related to the indirect- cost activities:

Activity Activity Cost Activity Cost Driver
Production scheduling $95,000 Production runs
Material handling $45,000 Material moves
Machine setup $25,000 Machiner setups
Assembly $60,000 Machine-hours
Inspection $8,000 Number of inspections

Marketing costs were determined to be 3% of the sales revenue for each type of door.

Required:

1. Calculate the cost of an interior door and an exterior door under the existing simple costing system.
2. Calculate the cost of an interior door and an exterior door under an activity-based costing system.
3. Compare the costs of the doors in requirements 1 and 2. Why do the simple and activity-based costing systems differ in the cost of an interior door and an exterior door?