Front hair in animation

I'm trying to create character-mod. So, i found that in "fear"-animation (sanity <=10) hairfront sprite doesn't attached to head. Of course, i bet y're wondering — standart characters has no front hair as different sprite, but why not? It is also founded in standart RoG (and SW).
In the uploaded image:
1 - headfront_0 sprite
2 - headbase sprite
red points - how shifted sprite location when character triggered by "fear"