Shaun,
I can't imagine any certification agency accepting 'first principles' data for inclusion in a flight manual or any computer program for predicting performance.
Sorry but you are wrong, the B777-200 only comes with "1st Principle" calculations, be they from AFP-DPI or SCAP. 1st Principles are also used by Embraer, Airbus and possibly Bombardier if they have finished writing the program.
Epsilon minus
AFM-DPI is based on first principles, for the B777-200 it replaces Chapter 4 of the AFM. You do not get a "2nd Principle" look up option. Are you trying to compare weights between AFM-DPI and a SCAP takeoff chart program? If so, the differences that you find are usually caused by the calculation methodology rather than the actual data, the methodology is manufacturer dependant. For example, Embraer offer 2 different calculation methodologies for 1st principles in the ECAFM, the 2nd option has a 40% faster calculation time for a small decrease in calculated weight. They do not offer 2nd principles.
Matthew
Flight test data in the AFM may have a line drawn through or beyond data points that is based on the first principles, so in some cases the "academic" difference between the two is minimal.
Not so, when Boeing offered us AFM-DPI for the B747-400, they showed an 8000 kgs weight improvement from J'burg. Its all from the same flight test data
Mutt