Differences between SAPP best-fit parameters from Bayesian scheme calculated with and without covariance matrix from spectroscopy (vertical axes) versus the reference parameters presented in Table 1 (horizontal axes). The uncertainty represents the 1 σ deviation. The grey shaded region represents the desired errors: 1% for T_eff, 0.05 dex for log g and [Fe/H], 15% for mass, 10% for age, and 2% for radius.