A couple of thoughts on the SoCalGas Complaint

1.  Perhaps you will want to emphasize this as being a computer system programming mistake -- not a billing mistake.  The point would be to distinquish that its not like someone sat down to bill SoCalGas, read the Global Settlement and agreed with SoCalGas' interpretation of how to bill this.  The point would be to show that we made a mistake in putting the computer programming in-place to handle this.  

2. I don't think the GISB 6-mo limitation went into effect until 4/97 -- so arguably it doesn't address this issue.  Nevertheless, I agree with the mistake language.  The GISB transcript excerpts that I clipped for Dari & Chris Sebesta for the IES dispute would be germaine (i.e. GISB didn't intend to bar mistakes ).

3. There is a FERC case that you might want to also cite for the concept of the equity of correcting past mistakes.  Transco discovered an error in their fuel calculation that was many years old.  FERC let them re-bill customers for something like $13 million dollars of undercharges.  I think this is a 2000 case.