Hmmm. Now I have to make an educated guess. The State Variations in the front of the manual (ie all the USG-n) probably reflect the additional requirements of CFR. Think about it. Do you know the state requirements for lets say Uganda? Neither do I. But if you were to ship some DG down there, all you'd have to do is look in IATA DGR & see if they had any other restrictions/requirements.
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rgds Rat