Hey, you calling me inconsistent?
1. When I shoot color neg, since it does not well tolerate underexposure, as that causes muddy color in the shadows: So I point my hemisphere at the lens, which biases my reading to factor in shadow areas.
2. When I shoot color transparency (or digital), since that does not well tolerate overexposure, as that loses details in the highlights: So I point my hemisphere at the [edit: LIGHT], which biases my reading to prioritize the higher areas of illumination (and the belief that the shadows will 'take care of themselves' while I try to preserve my highlight detail.
Most folks choose and use one technique and they don't really understand Why, or that there may be a better way under different circumstances...instead they think the other way is 'wrong'!