Mass ratio of Ni and Fe as a function of phase from the maximum light for Type Ia supernovae (SNe Ia), which are inferred from the emission lines from the late-time spectra. The relatively large error bars are primarily attributed to the approximately 40% relative uncertainty of the estimation from Maguire et al. (2018) that we have utilized. In accordance with the findings of Flörs et al. (2020), the predicted Ni/Fe ratio ranges for the delayed-detonation (DDT) models (Seitenzahl et al. 2013) are indicated by the yellow band, while those for the sub-Chandrasekhar mass (sub-M_Ch) models (Shen et al. 2018) are represented by the gray band. Both the Ni/Fe ratios derived from the observed spectra and those predicted by the explosion models are normalized to t → ∞ by assuming a rise time of approximately 18 days (Ganeshalingam et al. 2011).