Solar Mercury velocity controllers in UI don't return to "0" with physical MIDI knobs

I've reached out to Spitfire's team bout this issue, but they shrugged it off as if it wasn't a real problem.

In Solar there are vertical velocity slider controls for each of the three factors on either side (volume, pitch, and filter). The controls go up to +100 and down to -99 with 0 in the middle.

Assigning these to a physical midi knob (with a defined "notch" at the centre point) brings the following bug to light:

Using any of the few midi controllers I own, the knob's centre ("0") shows up on the Solar UI as +1 (not 0), basically because their values go from [-99] to [+100], instead of [-100] to [+100] . In other words, they don't have the same number of stops on either side of 0 --> so their 0 isn't actually in the centre: it's at +0.5, which gets rounded up to 1.

So when I have my physical instument knob at 0, the heard result isn't neutral. It's +1 :(

Anyone else have this problem? I'm particularly upset at this being dismissed as a "feature request" rather than a serious (and easily fixed) bug.