Average residuals for fits to 93 Fe lines, for two cases. It is quite clear that assuming a constant wavelength shift and macroturbulence is adequate when working in 1D LTE but assuming 1D LTE when dealing with high quality data is not. Top panel: the reduced-noise residual plot for all 93 lines. Bottom panel: the reduced-noise residual plot for 82 lines without other close absorption features. Lines not included in lower panel are noted with an asterisk in Table A.1.