>What I am asking is, if there is no Group A and no Group B, >then where will the power byte for group C be located in time? >Is it padded out to its normal position with a long string of >zeros? Not according to the author.
It is padded with zero so the remote flashes don't get confused.
>This is why I thought that the first 2 bits in the power byte >must be dedicated to addressing which group the power setting >was for.
No, it is not the case. I have updated part iii of my post to include an example in which group A is off but group B is on.