The R3 manual says that upshifts won’t work at very low engine speeds (how low?) and that the throttle must be held steady during a shift. Same with BMW although the throttle must be closed during a downshift.
Mine works butter smooth at like 2000 rpm. I don't know how low an engine speed you have to go for it to not work, but it works low enough for my careful lazy riding out of the neighborhood.
Under normal operating rpm the assist will work. Some throttle needs to be applied as it will not upshift with the throttle closed. It’s not “Rocket Science”.
Have you noticed any additional fuel consumption with the quick shift ?
And by the way, do you confirm that you can disconnect it ? Looks like it is possible when I look at the manual page 47 (though it seems secondary if one can still use the clutch (for every gear) while the quick shift is connected).