If you mean from shoulders down to hem, then maybe the less exposure on the lower area makes it darker and vice versa, where what may be too much light alters one's perception?
I once had to shoot two identical leather coats in the studio. To the eye, one was quite greenish and the other blue. On Ektachrome 64 they turned out identical, and could only be differentiated because the buttons were different.
Same light, same size on the trannie.
That said, can't guarantee on the same film - likely not, but processed in the same batch..
Rob