The standard process in SAP Project System (PS) to record work from multiple work centers on a single activity is to create separate, partial confirmations. For each confirmation, you specify the hours worked and the specific "performing work center" that completed that portion of the work. The system allows for numerous partial confirmations against an activity until it is finally confirmed. This method ensures that actual work, costs, and capacity loads are accurately recorded against the correct originating work centers and their associated cost centers, even if they differ from the work center originally planned for the activity.

B. Enter direct activity allocation assigning multiple work centers

Direct activity allocation (KB21N) is a Controlling (CO) transaction. It posts costs but does not update the activity's logistical data like status, remaining work, or schedule, which is the primary purpose of a PS confirmation.

C. Enter multiple work centers within a single confirmation

A single confirmation document in SAP is designed to record a specific quantity of work performed by one work center. The system does not have the functionality to input a list of different work centers within one confirmation entry.

D. Assign multiple work centers to the activity

In the master data of a standard internally-processed network activity, you can only assign one primary work center. This work center is fundamental for initial planning, scheduling, and costing of the activity.

1. SAP S/4HANA Documentation, SAP Help Portal: Project System (PS) -> Project Execution -> Confirmation -> Entering a Confirmation. This section describes the confirmation process, stating: "You can enter as many partial confirmations as you want for an activity until it is finally confirmed." It also details the fields available, including the performing work center, which can be changed at the time of entry.

2. SAP Training Course Materials: TS410 - Integrated Business Processes in SAP S/4HANA, Unit 7: Project System. The chapter on Project Execution explains that during confirmation (e.g., using transaction CN25), the performing work center defaults from the activity but can be overwritten. This supports the procedure of creating one confirmation for each work center that contributed to the activity.

3. SAP S/4HANA Documentation, SAP Help Portal: Project System (PS) -> Structures -> Network -> Network Activity -> Processing of Internal Activities. The documentation on maintaining internal activities confirms that the activity data includes a single field for the responsible work center, which is used for planning purposes. There is no provision for assigning multiple work centers directly.