Currently Set BPM (F0xx) is limited to F020 - F0FF (32 - 255 BPM) and even with the ability to set a high LPB value you still see people using figures outside of this range.
F000 still have to stop song so we’ll leave that but what I was thinking is use F001 - F00F and have it work in a similar way that the Volume change of the Retrigger command does.
IE:
1 -1
2 -2
3 -4
4 -8
5 -16
6 *2/3
7 *1/2
8 No change
9 +1
A +2
B +4
C +8
D +16
E *3/2
F *2
Giving you access to any BPM value and meaning you can change up (or down) without needing to convert current tempo to Hex and then insert incremental values.
It might be an alternative to make the BPM an automatable parameter in the master track? That would also allow playing with lfo/keytracking/midi automation on it.