You were told wrong. The manual explains this. "I" is TDC, and "H" is for ignition timing. But for the sake of checking valve clearance, it's close enough. What these marks are supposed to line up with is a small notch cut in the top of the top timing plug hole. Again, this is explained in the manual I guess I was told right. I just remembered backwards. This is why I always have the manual with me when I wrench.