Evolution of T_eff since the end of mass loss for selected He-core WD models. The red curve shows the CE track (M = 0.3208 M_⊙, M_H = 10⁻⁷ M_⊙) used for the secondary. Solid blue is the post-SRLOF model for the primary from Althaus et al. (2013) with residual burning L_nuc/L ≃ 0.25, and dashed blue is a variant computed here with increased residual burning (L_nuc/L ≃ 0.70) to illustrate its impact on the cooling. Coloured bars indicate the cooling ages inferred at the measured T_eff of each component, with their widths obtained by propagating the observational uncertainty in T_eff along the corresponding track (at fixed M and M_H).