How To Fix 53645 - SPF: tax indicator is not flat-rate; flat-rate is set

53645 - Overview

• Message type: E = Error

• Message class: 53 - Incentive Wages Data

• Message number: 645

• Message text: SPF: tax indicator is not flat-rate; flat-rate is set

What causes this issue?

You use a special feature for the public sector.The SPF is also taken
into account for dummy net calculation for the agreed gross amount. In
this way, only the flat-rate taxation is supported. An employee has a
different tax indicator in infotype 51 (supplementary pension fund).
The tax procedure was converted by the program to 'flat-rate'.

Error message extract from SAP system. Copyright SAP SE.

53645 - Details

• The SAP error message 53645, which states "SPF: tax indicator is not flat-rate; flat-rate is set," typically occurs in the context of tax calculations in SAP, particularly when dealing with flat-rate tax indicators in financial transactions. This error indicates a mismatch between the tax indicator set for a transaction and the expected tax treatment.
  
  Cause:
  
  Tax Indicator Mismatch: The error arises when a transaction is configured to use a flat-rate tax indicator, but the actual tax indicator assigned to the transaction does not support flat-rate taxation.
  
  Configuration Issues: There may be incorrect settings in the tax configuration, such as the tax codes or tax indicators that are not aligned with the flat-rate settings.
  Document Type Settings: The document type used for the transaction may not be configured to allow flat-rate taxation.
  Master Data Issues: The master data (like vendor or customer master records) may have incorrect tax settings that do not correspond to the flat-rate