National Bank has several departments that occupy both floors of a two-story building. The departmental accounting system has a single account, Building Occupancy Cost, in its ledger. The types and amounts of occupancy costs recorded in this account for the current period follow.

Depreciation Building Interest-Building mortgage Taxes-Building and land Gas (heating) expense Lighting expense Maintenance expense $ 18,000 27,000 8,000 2,500 3,000 5,500 Total occupancy cost $ 64,000 The building has 4,000 square feet on each floor. In prior periods, the accounting manager merely divided the $64,000 occupancy cost by 8,000 square feet to find an average cost of $8 per square foot and then charged each department a building occupancy cost equal to this rate times the number of square feet that it occupied. Diane Linder manages a first-floor department that occupies 900 square feet, and Juan Chiro manages a second-floor department that occupies 1,900 square feet of floor space. In discussing the departmental reports, the second-floor manager questions whether using the same rate per square foot for all departments makes sense because the first-floor space is more valuable. This manager also references a recent real estate study of average local rental costs for similar space that shows first-floor space worth $30 per square foot and second-floor space worth $20 per square foot (excluding costs for heating, lighting, and maintenance)