Schematic sketch of the relation between SMBH mass ℳ_∙ and absolute magnitude of the bulge M_B, with the solid diagonal line depicting the commonly adopted mean ratio ℳ_∙/ℳ_⋆ ≈ 0.002 (cf., e.g., Heckman & Best 2014) and the dashed line its expected change after correction for the δ_io effect. Arrows in the upper part point to the amplitude of δ_io and the expected fractional under-estimation of the bulge luminosity δL_B for the three LTG classes proposed in BP18. Bulgeless, pseudo-bulge, and classical-bulge galaxies may loosely be associated with type iA, iB, and iC LTGs in the mass intervals log(ℳ_⋆/M_⊙) < 10.3, ∼10.5, and > 10.7, respectively. Whereas δ_io increases with ℳ_⋆, its effect on δL_B is likely comparatively small for high-mass LTGs because of the prominence of their bulges, while it is expected to increase for intermediate-mass LTGs that simultaneously show a significant δ_io and a modest B/D ratio. We expect δL_B for low-mass LTGs to show a large scatter around a low median value because of their very low δ_io and B/D ratio.