Im not that technically minded but im pretty sure novation uses two cc s
To provide higher resolution i honestly would prefer it on the actual filter pot itself.
Just saying
The question is then, how big a resolution the pots have... that depend on the DAC which is probably some internal ADCs on either a microcontroller or the CPU... DSI have been using Microchip PICs earlier on, and I know that many of these are max 10bit resolution, so even if it's better than the 128 steps, 10bit "only" allow for 1024 discrete steps.
I'm not so sure though, that I'd want a greater resolution on the Cutoff knob because it's actually rather convenient that it's set in semitone steps... i use the self resonating filter for A LOT of presets, where the playability of the filter chromatically is important... it would take too long time to set the cutoff right if the resolution is bigger...
and also, the greater the resolution, the less movement it takes to change the values... you'd practically end up with a knob that might change values on it's own because the miniscule steps may change with small vibrations, where it will stand switching between two adjacent values constantly... setting precise values will become a nightmare with a 1024 resolution.
Besides, the MIDI SysEx dump is already set up for a value from 0 to 164 for the cutoff... it uses a single byte for this value, if you were to change the knobs resolution, you'd have to change the SysEx dump format as well, and make additional code to figure out which version of the dump it's receiving, otherwise it would not be backwards compatible with earlier formats.
So maybe if it is not obvious, it would require quite a few changes to create this feature... so I would not put my hopes up for it