Dr. Alyx Hemmings is employed by Mesa Dental. Mesa Dental recently installed a computerized job-order costing system to help monitor the cost of its services. Each patient is assigned a

job number when he or she checks in with the receptionist. The receptionist-bookkeeper notes

the time the patient enters the treatment area and when the patient leaves the area. This difference between the entry and exit times is the number of patient hours used and the direct labor

time assigned to the dental assistant. (A dental assistant is constantly with the patient.) The

direct labor time assigned to the dentist is 50 percent of the patient hours. (The dentist typically

splits her time between two patients.)

The chartfilled out by the dental assistant provides additional data that is entered into the

computer. For example, the chart contains service codes that identify the nature of the treatment, such as whether the patient received a crown, afilling, or a root canal. The chart not only

identifies the type of service but its level as well. For example, if a patient receives afilling, the

dental assistant indicates (by a service-level code) whether thefilling was one, two, three, or four

surfaces. The service and service-level codes are used to determine the rate to be charged to the

patient. The costs of providing different services and their levels also vary.

Costs assignable to a patient consist of materials, labor, and overhead. The types of materials

used