Well, his use of CoC was crude and clumsy according to Kaido. But Oda hasn't touched upon that again.
I'm starting to suspect that the plot required Luffy to be away from Kaido for a long while, so he needed him to lose. He simply came up with an excuse for it (crude CoC), but he didn't have any intention of making it an important aspect of the fight because at the end of the day, Luffy only had to lose to move the story in a certain direction (Yamato vs Kaido had to happen, Momo becoming large, ect)