Key Figures: Rough Workload Estimate 
The key figures used to analyze the workload are mostly updated from the application components Purchasing and Sales and Distribution.
The expected workload during workload processing (for example, from goods issue up to goods receipt) is the key feature of this procedure.
All key figures that refer to the workload are contained in the information structures for rough workload estimate and are expressed in terms of the following:

Creation of a purchase order
Creation of a sales order

Goods receipt posting
Goods issue posting

Difference between increase and reduction of workload
This key figure is not updated!
Quantity
Workload in terms of quantity (increase / reduction / delta).
This key figure is to be viewed in connection with the unit-of-measure load category.
Weight
Workload in terms of weight (increase / reduction / delta).
You can set the weight unit in Customizing for rough workload estimate.
Volume
Workload in terms of volume (increase / reduction / delta).
You can set the volume unit in Customizing for rough workload estimate.
Processing Time
Workload in terms of processing time (increase / reduction / delta)
The processing unit is Hour. The processing time is always stored in this unit.
You can use this key figure to plan staffing levels, for example.
Number of Document Items/Schedule Lines
Workload in terms of the number of transactions (increase / reduction / delta)
Shipping Material
Workload in terms of numbers (increase / reduction / delta)
This key figure (increase, reduction) needs to be updated by means of a customer exit. You can set the unit in Customizing for rough workload estimate.
See also:
How Key Figures are Calculated: Retail Information System