The UI combo content is just the displayed text string, in your case the combo would still send the values 0, 1, 2, 3.
What you describe can be achieved by editing another field called sysexExpression I think, which is normally set to “modulatorValue”. If you change that to “modulatorValue*32”, the modulator will send 0, 32, 64, 92 to the sysex string.
I tried this but found problems with parameter linking breaking. The current code is light enough and works well.