Airbus OEI predictions
 

QRH FPE-FPF Use of fuel penalty factors tables: "In case of failure impacting the fuel consumpition, the fuel predictions provided by the fms are no longer reliable (except in OEI condition)

FCTM AO 020: Once established at level off altitude, LRC performance with one engine out may be extracted from QRH.....

DSC 22-20-40-39: The system computes the flight plan predictions down to the primary destination assuming that the cruise phase is at the lowerof CRZ FL or EO MAX ALT.

Which one is correct?