Vorticey, whilst i agree with your thoughts re any tilting of the disc will require slightly more power, perhaps the less streamlined fuselage that a tailwind meets will create more requirement for power. The other consideration in a crosswind situation is, of course, that a right crosswind will require more power absorbing left pedal (US built heli's!!) to maintain heading and vice-versa. Then we could get into the topic of strong left crosswinds and LTE.....but lets save that for another day.
And to vfrpilot?? (spelling??) yes a B206 will run out of aft cyclic in a tailwind quiet easily, depending on loading etc.