Kernel density estimator of the mass distribution of models in the [α/Fe]=0.3 grid entering the 2σ box around the reference point at M = 1.0 M_⊙ and Δν = 0.06 in the [α/Fe]=0.0 grid at three different initial [Fe/H] values. Left: distribution of the masses at [Fe/H] = 0.2. The red line corresponds to error E1, the blue line to E2, and the green line to increased uncertainty only in effective temperature. The dotted lines mark the median of the respective distributions. Middle: same as in the left panel but for [Fe/H] = 0.0. Right: same as in the left panel but for [Fe/H] = −0.6.