I just tried with a track Drum (2*64/256) with Vel and Roll.
I get different level accents but they do not change when I adjust the levels of VelN and VelA then regenerate a pattern, only the original two values are used.
For example if you set VelN to 10 and VelA to 50, do you see the values get changed in the generated sequence? Mine just stays at the default of 100, 127.
thanks,
Luke