Degrees of mesh deformation not working

I’m rigging a shark, but I’ve come across a problem. I want to assign weights to some parts of the mesh for some bones that are not set to 1, but they all deform like they are all weighted at 1. I think pictures would explain my plight better :).

If I weight paint the vertices for this bone to red and rotate it, I get this, which is normal.

Then I’ll subtract from the group for that bone

Alas, the vertices with a weight less than one still rotate as if they had a weight of 1 assigned to them.
Here’s my blend:

It’s very annoying, so help would be greatly appreciated. Thanks in advance

If part of the mesh is weighted to one bone with 0.001 weight and not weighted to any other bones, the mesh will act like it has 1.000 weight to that bone.
On the last picture, if you want them green and blue vertices to not follow the Front_Head bone, you will have to weight them to a different bone aswell, Middle for example, so they have something to deform from.

Wow, thanks for the quick reply. Your advice worked solidly. Thanks again!