F22 is pretty stiff. I'd consider it an all-mountain boot that leans more toward the freeriding side of the equation. The F20 is more of an all-mountain boot that leans toward the freestyle side of the equation.
If K2 is telling you they'll swap them out, take them up on it. Shit happens. When you mass produce things, a couple of lemons will inevitably slip through occasionally.
"People say that marijuana smoking is going to get in the way of my career. I say to them that on the contrary, my fighting career is getting in the way of my marijuana smoking." -Nick Diaz