Yeah, not sure where you’re getting that. Even if you calculate the system change going from 16:49 to 16:47 is a 4.25% change and to 17:49 is a 6.25% change.
V-twins can certainly benefit from a ratio change to even out lumpy characteristics or flat spots that's that's sure. I had done a 15T counter-shaft sprocket on the Aprilia for this very reason.
Question. Is the speed calculated from gearbox rpm or wheel sensors on the FTR? I haven't looked. Any speed readout issues with ratio change?