A technician from Hitachi visited me last Saturday to see what was the flickering issue that I raised. Unfortunately the flickering did not show up. Exactly what I'm afraid about when I raised the complaint. If there were, they're so subtle that if you have not seen it before, you wont notice it. Some of the instances that I pointed out is considered by the technician as just because of the shift in the lightings from the scene.
He said that it could be my settings are too low. We even had a small argument on how to set, because I said that I based my settings on the THX Optimizer and also on how movies looked like.
He may think I don't know what I was talking about and was just paranoid.
I just shared to him the site of AVS forums so he can read about what I was talking about.
If other owners of Hitachi here can also raise this issue if they have it, maybe they'll believe it.