Dave,
Of course the Kamov people exaggerate the tail rotor losses, they make coaxials! Quote them all you wish, the real tail rotor losses for a single rotor helo are about 5% in hover at MGW and about 1% in cruise.
The S-76B tail rotor consumes 50 Hp while it hovers at 1050 Hp total power from the engines. You do the math, I am too tired of arguing with you!