A little while back I recall there was a discussion as to whether Magnetic Ride was a constantly variable system. My understanding was that it was, but I didn't get around to checking this again until recently. And the answer is: yes, it is constantly adjusting based on the driving inputs/situation.
The manual provides an example of this - saying that if the stiffness is set to the comfort mode, the system may choose to periodically increase stiffness during maneuvers such as cornering and braking: "damping is set somewhat harder for a brief period only as required, when rounding a curve and when braking." It also describes "imperceptible control processes" that can provide "individual modulation" to the dampers. So, while not a lot of information is provided (not a surprise - I don't expect they'll detail all of the programming in the owner's manual), it's clear that the system DOES, in fact, use variable damping even within a stiffness mode based upon analysis of the driving situation.
So, hopefully this clears up any confusion - you can select specific stiffness modes (comfort or sport) through the suspension button on the console, but even within those settings, the system will constantly be "individually modulating" the dampers based upon what it thinks needs to be done.
I know we often complain about the costs of magnetic ride (if the dampers fails), but it is quite a nice system, and I'm glad Audi included it.