Alexander, I'm not sure if this could help, but try -B.It allows you to set black brightness in cd/m^2. -f1 -k0 -A20 -B0.1 worked for me but my problem was color hue in darkest grays.-B0.1 was the lowest I could set in dispcalGUI.
Well I tried out -f1 -k0 -A20 -B0.01 and while R0 B0 G0 (black) got mapped to R3614 B2285 G2055, my shadows did appear to be devoid of any color cast or banding (which is nice).
Does the -A parameter even do anything when -k0 is set? From the manual it sounded like the -A parameter was dependent on the -k parameter being >0?