Protein Bars has two support departments, Information Systems and Personnel. The Information Systems Department costs of $120,000 are allocated on the basis of hours used. The Personnel Department costs of $30,000 are allocated based on the number of employees. Costs of the two operating departments are $60,000 for Fruit Bars and $90,000 for Nut Bars. Data on information systems hours used and number of employees are as follows:

Allocation Bases: Information Systems Personnel Fruit Nut

information hours used 600 600 720 480

employees used 10 20 40 120

Question: Identify and discuss one problem with using a single rate allocation method to develop charges for the use of services.