If it were called the Yata shield, I would concede that there may be a delay or flaw in how quickly the shield can change it's nature or deflect an attack.
It is not however, so as such we must all assume it follows the rules of a mirror which means instant reflection of whatever image is cast onto it.
Also, it is a remake of Yata no Kagami. An ancient japanese shield. This was said to relect all in an instant.
Do not insult me of being an Itachi fan who likes nothing more than to get right up there with him. I'm not. I like debates. I enjoy showing logic and explaining with facts and reference how strong my point is. In this case. I have a strong point, with reference and facts that back me up.
What I have been given as argument, is based on one individuals speculation. Not facts, no relevent material or info to back it up.
BTW: Retsu, it was a decent theory, so I apologise for the insult.