Left panel: Δlog L/L_⊙ with respect to the track computed with standard inputs from ZAMS to helium flash. The comparison was performed on a set of reduced tracks with the same number of homologous points. Right panel: central hydrogen abundance X_c vs. time (Gyr). In both panels, the red solid and green dashed lines show for comparison the output of models with standard physical inputs and Z = 0.005, 0.007 respectively.