My name is David, I’m a nurse from VA

I discovered MC Blog about 18 months ago. I’ve read TMMO, listen to his show almost everyday, but have not taken FPU.
Here’s my question:
Currenlty my only debt in addition to our home is my car loan. It’s $8600 with a rate of 4.9%. My employeer gives my the option of cashing in unused vacation time at 90% of our hourly rate. So my question…would it be worth cashing in about 100 hours to pitch at the car as a snowball? Or would I be losing 10% to save 4.9%?