Hmmm... From the research I've done, the only TSB I see related to magnets and the PCS is one adding a magnet. Something about replacing the one thin square magnet with the new larger round magnet. Also adding another to the filter body (like shown). In fact, that's exactly how the 2 year old serta unit I pulled apart was configured.
Do you have any more info on this? And thanks for the feedback!