The Koni FSD shocks "decide" which stiffness mode "to be in" based on how fast (the frequency) the dip or bump hits.
A rolling dip hits at a slow rate (low frequency) as compared to a crack or pothole, so the Koni FSD shock goes into it's soft mode ... which sounds like what you're experiencing.
You may be exactly right in soft not being the proper shock damping rate along with front end coil springs on rolling dips. I wonder what Koni designers would say about this?
For my stiff rear leaf springs, I DO NOT want permanently stiff shocks back there adding to the short throw leaf springs' stiffness on potholes and cracks - which are fast, high frequency bumps. For this I momentarily want no - or at least soft - shocks. The Koni FSD shocks are the only ones I can afford in which you get two rates of stiffness.