[Freesurfer] projfrac question

Dear Freesurfers

Hi

I was trying to look at the activation in different cortical layers in a single subject.

I ran my preproc-sess command three times, once without using -projfrac flag, once -projfrac 0.5 and lastly -projfrac 0.2

The activation patterns are exactly the same.

My voxel sizes are 1.1*1.1*1.1 .

My question is:

1-Is it normal that the activations do not change at all the more I get closer to white matter?

2-when I use -projfrac 0.2 , does it mean that I am averaging the activation between white matter layer to 0.2 of gray matter layer? Or is it averaging the activation between pial surface to 0.2 gray matter?

I hope my questions are clear.

Thanks

Mona