Variation of the parameters used in the figure of merit between consecutive time steps of a model for a star with 1.39 M_⊙ and Z = 0.007. The top, middle, and bottom panels show the differential evolution of the effective temperature T_eff, surface gravity logg and Δν, respectively. The vertical gray line indicates when a maximum timestep of 0.2 Myr was enforced between two models. The horizontal orange lines indicate the respective observational uncertainties for the given parameters. The bottom panel gives the timestep between consecutive models as a function of age.