Because you've got more kinetic energy, and more downward kinetic energy (downward speed) : you should apply the flare force (lift higher than weight) for a longer time, so you should flare higher : this is as per FCOM.
So what would be your typical flare heights in headwind and in tailwind ?
My understand of the tendency to float in tailwind is that the wind will tend to reduce close to the ground, so less tailwind will increase CAS hence will improve lift and prevent the A/C from landing.
Plus in ground effect the induced drag is progressively reduced.