I agree that the excess reinforcement factors would be different for each POI and load case. That is one reason most engineers conservatively ignore that factor. A simple or temporary solution is to set that factor equal to 1.

I believe that AASHTO is clear on this topic. The excess reinforcement factor simply uses "required As". This is interpreted as meaning that any force contributing to "As" should be considered (i.e., flexure, shear, & torsion). AASTHO then provides a means to calculated the required area of steel, considering those interactions, from Article 5.7.3.5-1 and 5.7.3.6.3-1. Article 5.7.3.5 specifically states "Any lack of full development shall be accounted for".

It is common practice to assume that the stress in the reinforcement linearly varies from zero stress at the end of the bar to full yield stress at the point of development. The effective area of steel (As,effective) would be calculated as shown below.

The As,effective would then be compared to As,required to ensure adequacy. As, effective would then be used to calculated the flexural capacity and all other strength calculations (shear, torsion, stress, etc)”