bone parenting performance problem

I have created a simple face with a single bone used for rotation of it. I parented the nose to the bone, using a vertex group. Then I parented the other objects (eyes, ect…) to the bone using the option Parent (to bone).
Everything folows the bone perfectly, but it causes a bad performance hit in the 3d display while trying to animate him. I have created full characters with armatures throughout and not experienced this type of performance hit. Anyone know why this is? I have included a link to the .blend

Also, experimenting with using bones for driving the ipo’s of shape keys to curves (his mouth), is there a way to control the amount of deformation? Right now it is too sensitive, and one corner of the mouth deforms in the opposite direction. I cant seem to get a curve out of the blue line that defines that particular shape.

here is a link to the blend (.ZIPped)

Noone has responded to my question yet. Maybe is it a stumper?
I was able to recreate the problem again, doing everything the same way as before.
I then tried a different method. Everything is the same, except instead of using a bone for the nose, I just mapped the control to the ipo of the object itself.
This new method greatly increased performance. Even when I turn up the subsurfing in the main window to 2 and 3, the controls still respond smoothly. I guess there is some issue with parenting too many objects to one bone.
Here is the new .blend