Sounds like a useful, musical, design. If someone with an audio interface has a D-350/800/800+, it would be great if they could run some loopback tests to get a frequency response plot of the controls. People have done that with the VT Bass and other devices, and it can be enlightening if you know what you're seeing. I spend quite a bit of time with graphic EQs, moving in 0.1dB increments, so I have a grasp of the sound of various parts of the audio spectrum. Frequency masking effects can be a fascinating rabbit hole, and sometimes 0.1dB makes a significant difference in the audibility of different aspects of a mix.