Thanks to everyone who replied to my query. I called apple support - they could not help and instead arranged a genius bar visit.
Question: What is the point of the genius bar visit, lugging a big imac 27 all the way to the Apple store? Either they will say the SMART message is incorrect and my drive is fine or they will say the drive is likely to fail. If the former, i'm fine. If the latter, I need to move to a new drive or get a new mac - either of which will require a restore from backup or data transfer from the present failing hard drive.
Since i backup religiously to two external drives (using time machine auto backup) and use backblaze for further redundancy, AND have most of my files on dropbox anyway, why go to the Genius bar? Let the disk fail whenever it does and then deal with it using my multiple backup options. Makes sense, or am i missing something - is there really any value the Genius bar folks can add to my situation?
THANKS!!