BEWARE!!!!!!!! Be sure to check your credit card statements! I used my Platinum Companion Certiricate a few weeks ago, following the redemption process exactly as described (by booking through delta.com/redeem and booking only the eligible flights it showed me for that certificiate). 4 days later, I was looking at my credit card statement online, and saw I was charged for TWO FULL TICKETS! Not at all the price I was shown on my confirmation page online when I booked it. Delta web support then had the audacity to blame ME for taking 4 days to notice THEIR problem as to why it was taking well over an hour to reissue the companion ticket correctly. So, just double check what you're actually charged!