Relative error with respect to the input mock MACS cluster on the average surface mass density Σ(< R) as a function of radius (from G1) for the multi-plane MP (left panels) and single-plane SP (right panels) best-fit models of the mock MACS mass distribution compared to the input model (in dotted black). Upper panels: relative error on the Σ_eff (< R) (for source at redshift z_s = 3) for the total cluster, i.e. halos, members and perturbers. Central panels: relative error on the average surface mass density of the halos for the different models. Bottom panels: relative error on the average surface mass density of the cluster members only. We note that in the total multi-plane configuration the Σ_eff (< R) is relative to the total deflection angle, as explained in Sect. 2.1.