yes, in general you should get the full modulation range if you put them halfway and then feed a modulation signal into the modulation inputs.
however, in the case of the midi module, if you are feeding a signal from the midi module cc outputs into the modulation inputs, you might have to offset the signal because the range is 0 to 1 (0 to 5V) for MIDI CC values 0-127.
You can apply an offset by using the DC module, feeding its output signal into the same modulation input, or alternatively you can adjust your parameter value to a lower value so that the resulting summed signal gives you the range you want. Just play with it and you’ll see what I mean.
The DC module would just give you a DC offset though. It wouldn’t scale your modulation signal.