@alhug thanks .
Not sure what I'm doing wrong, but if I set the knob range to -12 to +12 with a step equal to 1 (like in this case I guess), every step corresponds to an octave shift.
@Giuseppe If you go to Tools >> Record one second audio file, and then hold a key to playback a sample over the loop points it will render an audio file that you can open in a wave editor and see if the crossfade is being applied or not.