Since pacta sunt servanda, SS would need to be grandfathered. But that does not put a floor on BI, you are free to set BI below SS. This may not sound fair, bu

Since pacta sunt servanda, SS would need to be grandfathered. But that does not put a floor on BI, you are free to set BI below SS. This may not sound fair, but is no more unfair than introducing new environmental regulation without punishing all past acts which would be in violation of new regulation.