Smoker's Cough

I've peeked around the site and have read about the bleach & redye method.

My question is, is the dye necessary even if your hair color doesn't noticeably change?

From my (admittedly limited) understanding, the redye is used to simply return the hair to its original color and not as a way to remove the THC metabolites. Am I wrong?

And since I'm starting a new thread, I might as well describe my own situation...

I smoked from January to February - 2 to 3 joints per week - so I've been clean for about 50 days.
I have a hair test next Friday - will be clean for about 57 days.
Tonight, I'm planning on using baking soda for 15 min and bleaching my hair. I'll continue to use baking soda and Tide everyday until next Thursday and then bleaching again. I have ordered Zydot, so I'm hoping to have that in my possession before the test.
This will be done on my underarms and chest because I don't have enough time to grow the hair on my head.
I'm african american, btw.
Any more suggestions, etc?