= Solution
Many lower-luminosity <elliptical galaxies> have dense central stellar cusps, giving far more photons and kinematic tracers near a central <black hole> than the shallow depleted cores common in massive <elliptical galaxies>, as measured in https://arxiv.org/abs/astro-ph/9610055[Central galaxy profiles]. Thus \b[central <surface brightness> can make the smaller black hole easier to measure], despite its smaller mass, whereas sparse central tracers and uncertain stellar orbital anisotropy weaken measurements in a large core. This is not a universal mass ordering: the <black-hole sphere of influence> $r_{\rm inf}\simeq GM_\bullet/\sigma^2$ must still be sufficiently resolved in angle, so distance, <velocity dispersion> and <angular resolution> also matter.
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