Comparison between best-fit SFR, E(B − V), and age from SED-fitting at fixed metallicity (Sect. 3) and those obtained when leaving metallicity as a free parameter. Only three objects are fitted at the right metallicity (black crosses). Ten objects are found to have an incorrect best-fit Z = Z_⊙ (red), one object (green) is fit at a metallicity lower than the real one. Above each panel is the average discrepancy between the results of the two SED-fitting runs considering the whole sample (black) and the objects with Z = Z_⊙ SEDs in the free metallicity run (red).