Lowering the AB eating to the desired lower one is good airmanship in this case, alternatively, manual braking to disconnect the higher auto brake selected the other option.
All very complicated and unnecessary fiddling about. If you land with autobrake MEL'd u/s, should you declare Mayday or simply PAN? Or just land and use normal manual braking like ordinary pilots have done so in the past 50 years. Much ado about nothing, IMHO