Relative age difference Δt/t = (t_BaSTI − t_LPCODE)/t_BaSTI as a function of luminosity for carbon-core sequences. No latent heat release upon crystallization is assumed. Dash-dotted line, dashed line, and solid line correspond to different input physics as specified at steps 1, 2, and 3 in the text. In particular, at step 3 the input physics assumed in both codes is exactly the same (see text for details).