The preceding figure highlights the following main settings for defining the capacities of a work center:
On the Capacities tab page, you can specify the individual capacity categories (labor, machine, for example) of a work center. Each capacity category has its own available capacity.
The formula for calculating the internal processing requirement defines how capacity requirements are to be determined from the activity details. Usually, only the Work field is used from the activity.
The distribution key of the work center is only used by the system if no distribution key is specified in the activity.
Availability Capacity
Capacity Requirements

Scheduling determines the capacity requirements using the scheduled dates for the service to be performed. The system determines the capacity requirements using the formula in the work center and the work from the network activity.
Capacity requirements can also be determined for externally processed activities. To do so, you must set the Scheduling and Capacity requirements indicators in the control key. Capacity requirements are determined in the same way as internally processed activities.