Comparison between the EPIC and RGS measurements of the O/Fe abundance ratio in most objects of our (0.05 + 0.2)r₅₀₀ sample. The blue dotted line shows the one-to-one EPIC-RGS correspondence. In our fits we alternatively fix the N_H to the weighted neutral+molecular values calculated from Willingale et al. (2013), and leave it free within the ranges given by Eq. (A.1). The two approaches are shown in red and black, respectively.