assess the Keplerian motion of the maser spots. Among the self-consistent models (`Torus`, `MYTorus` coupled, `MYTorus` decoupled) the latter one gives the best $\chi^2$, although spectral parameters are consistent among all of them. A `Torus` model points toward smaller opening angles (i.e. larger covering factor, $\sim$ 0.9) which could account for the line emission ($\chi^2$/$\nu$ = 761/684). Fitting with `MYTorus` in coupled mode underestimates the line feature ($\chi^2$/$\nu$ = 803/684). This could be due to supersolar iron abundance, a broad range of $N_{\rm H}$ with different covering factors, or to a covering factor greater than that of the model, as suggested by the `Torus` model. Decoupling `MYTorus` does not change the general results, while the back-scattered radiation seems to be favoured over the vanishing front-scattered one ($\chi^2$/$\nu$ = 729/682). The fit can be improved adding a scattered power law below 5 keV, which brings the reduced chi-squared to $\chi^2$/$\nu$ = 693/681 (Figure \[fig:subfig7\]). According to the best fit model, NGC 4388 is a Compton-thin ($N_{\rm H}$ = 4.2 $\pm$ 0.5 $\times$ 10$^{23}$ cm$^{-2}$) transmission dominated source, and our results agree with the constraints implied by its known hard X-ray variability on scales of days and months [@2011MNRAS.417.1140F]. The `MYTorus` best 