Automatic account assignment in SAP S/4HANA, configured via transaction OKB9, provides a default Controlling (CO) object (e.g., cost center, profit center) for postings to G/L accounts with a primary cost element category. This mechanism ensures that when an expense from an external source like Financial Accounting (FI) is posted, it has a corresponding CO assignment. The values proposed by this configuration are defaults intended to prevent posting errors when a CO object is not manually specified. As default values, they can be manually overwritten by the user during transaction entry if a more specific assignment is necessary.

B. It is not defined for secondary cost types, as these are used for internal CO allocations where objects are determined by the allocation logic itself.

D. Substitutions are processed during document entry and can overwrite default values from automatic account assignment based on more complex, predefined rules.

1. SAP Help Portal (S/4HANA 2023): Automatic Account Assignment. This official documentation states

"In this activity

you can specify an automatic account assignment for primary cost elements... When you post to such a primary cost element

the system uses the default account assignment." This confirms that the feature applies to primary costs (Option A). The nature of a "default" in SAP systems implies it can be overwritten (Option C).

Specific Location: SAP Customizing Implementation Guide -> Controlling -> Cost Center Accounting -> Actual Postings -> Manual Actual Postings -> Edit Automatic Account Assignment.

2. SAP Help Portal (S/4HANA 2023): Secondary Costs. The documentation on secondary cost elements (now G/L accounts with secondary cost type) describes their use for internal allocations like assessments and settlements

which have their own sender/receiver logic

distinct from the OKB9 mechanism. This supports the exclusion of Option B.

Specific Location: SAP Help Portal -> SAP S/4HANA -> Enterprise Business Applications -> Finance -> Management Accounting -> Cost Element Accounting.

3. Salmon

J. (2021). Controlling with SAP S/4HANA (2nd ed.). SAP PRESS.

Page 105

Section 3.4.3: The text explains that automatic account assignment (OKB9) is used to "define a default cost object for postings to primary cost elements." It further clarifies that this is a fallback mechanism

implying that a manual entry will take precedence

thus supporting both options A and C.

4. SAP Help Portal (S/4HANA 2023): Validation and Substitution. The documentation on financial document processing logic explains that substitutions are used to automatically replace values in fields during transaction entry based on defined prerequisites and rules. This process can override any default values

including those from automatic account assignment settings. This refutes Option D.

Specific Location: SAP Help Portal -> SAP S/4HANA -> Enterprise Business Applications -> Finance -> Financial Accounting -> General Ledger Accounting (G/L) -> Tools -> Validations

Substitutions

and Rules.