differences between 2k10 headshapes and 2k11 haedshapes

we know that the 2k10 headshapes can't be simply imported into the 2k11 cyberface files,
what differences do you think they have?

I mean, I have compared to the two headshapes of a same player,
their heads look exactly the same,
their basic components like eyes, jaw, upper and lower teeth are also the same,.

Some mentioned about their tongue being different,
but I can't really see it in the headshapes.

the only difference I've seen so far is that they are in different sizes.

I really hope that we can find out the actual differences and make a convertor or somethin g

I think only the vertexes are not the same