I'm trying to figure out how to incorporate P-D affects into this calculation for a partially grouted masonry wall using strength design provisions. Anyone have any ideas?

I am trying to follow the recommendations per MSJC-13 or other editions. However here is the basic Idea:

Lateral loads cause lateral deflection in the wall. These deflection can be found by first order methods. However the vertical loads amplify this deflection. So the code suggests and iterative process of:

Find deflection of wall based on effective moment of inertia.
Find the moment due to axial loads x the deflection.
Add this to the total moment. And solve again until a 5% convergence is reached.

So this is an iterative process as...
The effective moment of inertia used to find the deflection depends on the depth of the Neutral Axis (NA).
The depth of the NA depends on the total moment.
The total moment depends on the the deflection.
The deflection depends on the moment of inertia.

Attached is my current calculation and an old manual iteration calc.

Any suggests are appreciated, Thanks!!