Spectrum-to-spectrum abundance scatter of individual iron lines as a function of wavelength, EW, and the distance from the center of the spectral order. Outliers at 3σ level are excluded. The red and blue symbols correspond to the lines that in the 2D spectrum are observed in multiple and single orders, respectively. The boundary wavelength region (at~5250 Å) of the blue- and red-arm detectors is indicated by the rectangle. EW measurements are performed on the S1D spectra.