Diapason Inc Dec with rotary encoder MIDI CC

Hi, I've mapped a rotary encoder to Inc and Dec Diapason. What I'm finding is that the step size seems to depend on whatever range I specify, divided by 128. So I can get it to increase by 1Hz for each tick of the knob if I specify a range from 100 - 227.

Is there any way to get a mapping that's more in line with a rotary encoder? I'd love something that increases logarithmically starting at say 440 and since it's a rotary encoder, it doesn't make sense to constrain the range in terms of 128 values.