Absolute abundances from individual neutral iron lines A(Fe I) for the reference object S55974 vs their EP, REW, and wavelength (from top to bottom) using the atmospheric parameters from Cabrera-Ziri et al. (2019). Blue crosses denote abundances from the Fe I lines and green circles indicate abundances from the Fe II lines. The solid blue lines are linear fits to the Fe I data and the black line in the bottom panel is a horizontal line at the average value of the iron abundance.