I do not have a copy of the NFGC, but the International Fuel Gas Code describes the hybrid method as sizing the piping from point of delivery to the most remote regulator and then sizing the piping from the regulator to the most remote outlet. I would assume the methods would be the same
This method, which splits the system into distinct pressure regions, can be used regardless of the pressures in the piping, either upstream or downstream of the regulator.
If using tables, be careful to stay within the pressure drop constraints listed for the tables. But, be careful, even to do that.
I generally do not use the tables, since sometimes the above constraints list pressure drops in excess of 40% of the inlet pressures and the equations used to generate the tables are typically constrained to no more than 20%. So I would question any table that exceeded 20%.