Median of the 408 analysis-independent values, for both the curve of growth (black circles) and iterative modelling (blue circles) methods, are plotted against the stellar parameters of the seven benchmark stars. The median of the σ_grid values are denoted by the blue error bars. The overestimation of the relative to the values can be seen. Apart from V I, we do not find any clear trends with respect to the stellar parameters for any of the 14 remaining species in the analysis-independent subset of lines.