YES...it does work...simply go to your Gmail account online, then contacts...then scroll down and select the ones you want to get rid of, then press delete. A message pops up says these changes will also be deleted from other records, Google Voice...Android...iPhones (boooo!)...etc...confirm, and you are done. I have nearly a 1000 contacts, and finding the doubled up ones took me less than 5 mins.
Nice work around, even if i do say so myself!!!
(Still would be nice to have this function on the phone and/or in Gmail...Gmail should automatically scan your contacts for duplicate data sets, and ask if you want them deleted).