New Successful way to swim the 100 Freestyle?

I been thinking.. as i watch the video of James magnussen swimming the 100m Free at the world championships i realized that his first 50 looked like the hybrid freestyle and his second 50 was more of a shoulder driven stroke.. Couple Months later the video of Cesar Cielo popped up on the internet from the Panamerican games and in his 400m relay, his first 50 was the hybrid freestyle and his second 50m he went back to his shoulder driven freestyle. he went his best 47.07 relay split and 47.84 in the 100m Free My question is that by doing the hybrid for the first 50 and then shoulder driven for the second 50 is now the correct way to swim the 100 free? (cesar cielo 100m free 47.84) Pan-Americano 2011 - Cesar Cielo conquista o 3° ouro para o Brasil - YouTube