For the considered test cases, we could demonstrate that the inclusion of such a densitybased correction improved the accuracy considerably, while adding little computational overhead. For idealized polypeptide structures, the db-MFCC-MBE(2) scheme is able to bring down the fragmentation errors to ca. 1 kJ/mol for all considered secondary structure elements. For proteins, we are able to reach errors below 1 kJ/mol per amino acid. However, these still correspond to substantial errors in the total energies of the proteins, even though the db-MFCC-MBE(2) scheme clearly improves upon the corresponding energybased scheme.