SAP Message 53645 - SPF: tax indicator is not flat-rate; flat-rate is set

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