While this is true for most matches, one player is simply winning his matches and moving on to the next round. Pavel Eljanov started the event with 2-0,2-0,2-0 before easing up with in round 4, tying 1-1 with Jakovenko. However he won the first set of rapid matches 1.5-0.5, and then eliminated Nakamura 1.5-0.5 is round 5. He is +7 in the classical games (7 wins, 3 draws) , which is 4 points better than the remaining players!
Here is the first game of his match against Nakamura, where he gave up 2 pieces for R+2 pawns. To borrow from computer chess R+P v 2 minors generally favours the minors by half a pawn, but R+2P is around half a pawn better for the R. This seemed to be confirmed in this game, where Eljanov looked better after the swap, but still had to work to finally convert.
Eljanov,Pavel (2717) - Nakamura,Hikaru (2814) [E06]
FIDE World Cup 2015 Baku AZE (5.1), 23.09.2015