Another set of the spectral models that do not fit to the observed spectra. The solid curves show the synthesised spectra for the model in which the mass fractions of ⁵⁶Ni and ⁵⁸Ni are decreased by a factor of eight as compared to the reference model. The dashed curves adopt a pure C+O composition (plus the progenitor metals) for the high-velocity component. The grey lines show the observed spectra (see the caption of Fig. 7 for details).