I did some reverse engineering and I did find this logic actually:
Band_0? Band_1? ? ? ? ? ?Band
0? ? ? ? ? ? ?0? ? ? ? ? ? ? ? ? ? ?Never (no bands selects this)
0? ? ? ? ? ? ?1? ? ? ? ? ? ? ? ? ? ?20m
1? ? ? ? ? ? ?0? ? ? ? ? ? ? ? ? ? ?30m
1? ? ? ? ? ? ?1? ? ? ? ? ? ? ? ? ? ?40,60,80m (all of these three bans selects the same BPF)
no conclusion yet. Just I wanted to share this.