cartoony Head squash!

[sathish Rigger]

Its regarding problem of head squash and stretch in toony style setup using spline IK system in maya.
I followed the setup explained in the book of Jason Osipa's - Stop Starring Facial Modeling and Animation.

Here is the setup, I used:

1. Main rig - simple neck and head joint, control the head mesh via skin cluster.
2. Squash rig - spline IK joint chain (which is child of head joint) from neck to head, control Lattice of the duplicated head mesh.
3. Apply blend shape of duplicated mesh on main mesh. So if we adjust spline IK chain, main mesh will affect.
4. I also parented spline IK head ctrl objects under chest ctrl.

Here is the problem:

When I move the chest ctrl, Head mesh gets double transformation. Where the mistake will be? Help me guys.

(Deformation order of the head is right. The Lattices of head is not child of any objects)