D3, you will have to explain those diagrams more clearly. The text is hard to read, and we are not familiar with your simulation. The polar plots slightly differ from one plot to the next, but i have no way of understandiing what this is telling me. Why is the plot slanted?
Agreed that in hover it is the induced drag which goes down. To me, the reason for this is the induced downwash velocity goes down. The blades will see a similar static pressure difference top to bottom (since heli weight has not changed), but the pitch will be less. So if you use axis plane as datum then the lift vector is less rearwards, so torque hence power is reduced.
It would help if you described how you accounted for the reduction in downwash velocity from ground effect. To me this is a complex CFD problem (using vortices or finite difference), and i am not sure how you can do such a complex calculation real time. Prouty would describe the way that the downwash wake contrction becomes reduced as the ground is brought nearer, so velocity goes down.
If you wish email me directly, since i am worried that this thread may be losing the pilot community for which it is intended.