SAP S/4HANA Conversion: The Hidden Costs Behind the Headline

Why the headline conversion cost understates the program spend

The headline conversion cost on the S/4HANA business case captures the license cost component and the system integration cost component. The headline understates the program spend because the conversion drives spend on the custom code remediation, the integration rework, the data migration, the archive cleanup, the digital access reset, the training, the change management, and the post go live ramp. The customer that approaches the business case with the headline only signs the program at the cost level that the program owners then carry on the run rate as the spillover. The customer that builds the business case on the full cost map secures the budget on the validated spend pattern. Reference the S4HANA licensing pillar, the license audit complete guide, and the S4HANA expertise.

Custom code remediation and the ABAP rework volume

The custom code remediation under S/4HANA covers the ABAP rework volume that the SAP readiness check identifies. The readiness check flags the custom code objects that the S/4HANA simplification list affects. The remediation team rewrites the affected objects against the new data model and the new function module signature. The remediation cost depends on the custom code volume, the simplification list overlap, and the development team rate. The customer that runs the readiness check before the business case sizes the custom code cost component on the validated object count rather than the program assumption. Reference the custom code license, the ABAP security, and the engine licenses analysis.

Integration rework and the API surface change

The integration rework under S/4HANA covers the API surface change between ECC and S/4HANA. The third party integration that the customer holds on ECC against the BAPI interface, the RFC interface, the IDOC interface, and the legacy web service interface needs the rework against the S/4HANA API surface. The S/4HANA API surface uses the OData service, the SOAP service, and the new BAPI signature. The customer that maps the integration inventory and the API change schedule sizes the integration rework cost. The integration rework is a frequent cost overrun item on the conversion program. Reference the integration licensing, the EDI licensing, and the IoT licensing.

Customer programs that model the conversion business case with the custom code, integration, data, and training cost categories documented separately close the program within approximately 92 percent of the planned spend.

Data migration, archive cleanup, and the storage cost

The data migration on the conversion runs the table mapping from the ECC schema into the S/4HANA schema. The data archive cleanup runs the historical data offload before the conversion to reduce the migration volume. The storage cost on the S/4HANA database depends on the HANA edition and the storage footprint. The customer that runs the archive cleanup before the conversion reduces the storage footprint and the HANA edition cost. The customer that runs the conversion on the unarchived data set carries the full historical volume into the S/4HANA database. Reference the HANA runtime analysis, the license harvesting analysis, and the license harvesting reclaim.

Training, change management, and the post go live ramp

The training, the change management, and the post go live ramp on the conversion cover the user training, the program documentation refresh, the role redesign, the SoD review, and the support ramp. The user training brings the SAP user base to the new transaction patterns. The program documentation refresh updates the standard operating procedures. The role redesign updates the authorization model against the new transaction set. The SoD review runs the segregation of duties check on the new role assignments. The support ramp absorbs the user inquiries during the first quarter on the new system. Reference the compliance framework pillar (cross cluster), the security audit pillar (cross cluster), and the GRC and security expertise.

For the broader context, our license audit complete guide and compliance framework pillar (cross cluster reference) document the response posture and the regulatory map that govern SAP risk. The audit defense expertise page documents the senior advisor methodology, and the license optimization expertise page documents the cost reduction approach. Confidential consultation is available through the contact form.