Unlikely. Plextor, with the exception of announcing DL support in a firmware upgrade, never has pre-announced firmware and certainly has never pre-announced a feature reduction. Coming from a tech support source, I'd take that info with a grain of salt. TS is usually the last to know...been there, done that..
As mentioned above, if the media production results in crappy discs, PoweRec is designed to compensate. I doubt Plextor will go through a wholesale change to the write strategy to remove a particular ADIP for each speed supported when they already have a feature to correct for sloppy media.