lokius has balanced differential front-end stage, so it uses both phases of the XLR input signal and will be therefore 6dB louder in active mode vs bypassed. SE (RCA) in -> SE (RCA) out does not have such a volume change, as the differential portion of the input gain stage sees no signal on the negative input phase in that situation.
The amount of correction (max +/- dB) varies depending on which band is being corrected.
from the website specs page:
Bands: 20Hz, 120Hz, 400Hz, 2kHz, 6kHz, 16kHz
Adjustment: +/-12dB at 20Hz and 16kHz, +/-9dB at 120Hz and 6kHz, +/-6dB at 400 and 2kHz
So best to compensate using the volume control on pre-amp, HP amp, etc., instead of trying to adjust all six knobs an equal amount.