All computations displayed involve various areas for corrective factors, as slowly is beginning to emerge from this thread.
The one factor not yet attended to is the difference in pitch attitude and thrust vector direction as a result of that, affecting the forward thrust vector and conversely has a vertical element.
All those guys having worked out the tables have made many iterations having based their data on flight tests etc, give them credit where it's due and let us accept their derived and published data rather than try to find the loops in the simplified equations presented to us simplistic pilots (compared to those in the know).
I'm sure there are more and unmentioned (this far) variables which may contribute as well, but let us get to grips with the fact that we are not going to find out ALL the variables and get access to test data to look over.
Basic question on page 1 about margins when using assumed thrust has been answered. Several factors have been mentioned which affect it.