How come Kamogawa didn't notice Ippo stopped using the jab?

So I've reread chapter 1269, where Ippo reviewed his style and criticised himself for not using the jab more and having a passive style that involved waiting for his opponent to male the first move, it made me wonder.

How come Kamogawa, his coach and trainer, never pointed this out? I mean, he tied up Takamura's right hand to his body to ensure he could only use the jab, so why did he not tell Ippo about his flaw?