Final answer:
The method that allocates costs by explicitly including all the services rendered among all support departments is called the Step-Down Method.
Step-by-step explanation:
The method that allocates costs by explicitly including all the services rendered among all support departments is called the Step-Down Method.
In the Step-Down Method, each support department allocates its costs to other support departments and to the production departments based on a predetermined hierarchy.
For example, let's say Company ABC has three support departments: IT, Human Resources, and Accounting. The IT department allocates its costs to both the Human Resources and Accounting departments, and then those two departments allocate their costs to the production departments.