The suggestion card computes the masking margin for exactly your setup: more voices mask each other (so the bed can sit closer, plateauing around four), a mixed-gender or wide-panned cast stays separable (so it leans deeper), and a bed that is thin or scooped where speech lives needs extra room. Declaring headphones credits wide panning with a small adjustment. Speaker playback does not receive that adjustment.
The gold tick on the margin control is the computed starting point and the green band is the suggested range. “Reset to suggested” restores that starting point in one move. Everything stays advisory: drag any fader yourself at any time.