Evolution of the features and PCA performance for the target (DC21bwbfe/SN2021bnv, Type Ia SN; r band); positive flux cases only. The color scheme is the same as in previous Figures. Here, feature Nos. 3, 5, 11, and 12 are less effective than the others. Compared to Appendix C, which uses a larger set of features, here PCA generally has better separation (higher EVR). However, when poor weather leads to low S/N (blue points in the middle of the exposure sequence with low teff), using more features as in Appendix C gives slightly better results (higher q _P).