Top panels: time variation of the F814W magnitude of the 0.8 M_⊙ and 2 M_⊙ model stars shown in Fig. 2. The grey and yellow regions refer to the F814W magnitudes of the RGB and AGB boxes introduced by H23. The evolution of the 0.8 M_⊙ model star is divided into the RGB (blue line) and the post-flash (red) parts. The magenta and green lines refer to the evolution of the 0.8 M_⊙ model star, under the hypothesis that 0.1 M_⊙ and 0.2 M_⊙ were lost during the RGB phase. Bottom panels: time variation of the F814W magnitude of 1.5 M_⊙ and 2.5 M_⊙ stars.