$1.$ Since sales dollars represents "ability to pay," it is superior to most other bases used for allocating or charging service department costs$\mathrm{.}2.$ For performance evaluation purposes, any variance over budgeted fixed costs in a service department should be the responsibility of the service department and should not be charged to the departments that use the service$\mathrm{.}3.$ For performance evaluation purposes, the actual fixed costs of a service department should be charged to the departments that consume the service in proportion to the actual services provided to the consuming departments during the period$\mathrm{.}4.$ Whenever possible, service department costs should be separated into fixed and variable costs and charged separately to operating departments.