It turns out Mary rarely used assist level 6 and had no use for levels 7 and 8 of my derated BBS02 configuration:
LC=15 ALC0=0 ALC1=5 ALC2=7 ALC3=16 ALC4=25 ALC5=37 ALC6=51 ALC7=67 ALC8=85 ALC9=100
Level 9 must be 100% of the maximum motor current so the throttle can apply full power to get out of the way in a hurry.
The new and even more derated configuration allows small-step assist level selection for our usual riding, at the cost of an unused huge step to level 9 for the throttle:
[Basic] LBP=42 LC=18 ALC0=0 ALC1=4 ALC2=6 ALC3=9 ALC4=15 ALC5=20 ALC6=25 ALC7=30 ALC8=40 ALC9=100 ALBP0=0 ALBP1=100 ALBP2=100 ALBP3=100 ALBP4=100 ALBP5=100 ALBP6=100 ALBP7=100 ALBP8=100 ALBP9=100 WD=12 SMM=0 SMS=1 [Pedal Assist] PT=3 DA=0 SL=0 SSM=4 WM=0 SC=20 SDN=4 TS=15 CD=8 SD=5 KC=100 [Throttle Handle] SV=11 EV=42 MODE=1 DA=10 SL=0 SC=5
LC=18 line limits the maximum motor current to 18 A, rather than the rated 24 A, which may improve controller MOSFET longevity; reliable evidence is hard to come by. Controller failures seem to happen more often to riders who value jackrabbit acceleration on harsh terrain, so it may make little difference for road cyclists.
So level 5 now selects 75% × 20% = 15% of the motor’s nominal 750 W:
Call it 115 W: we’re both getting plenty of exercise!