From everything I've read and experienced, your idea is not a good one. It takes three days to break properly. Between cleanses, your body needs to rebuild. Basically, the MC takes the trash out of your system. Doing the MC for ten days (a good start at taking the trash out) then taking a short break of removing trash from your system to load it back up with garbage for a day or two sounds a bit off to me.
The Master Cleanse is not really something you want to play around with like a fad diet. It is not Really for weight loss. It's actually a little tricky to make it work as a permanent weight loss plan. Since while you are on the MC, your metabolism is essentially shut down, when you eat for that day or two, you'll most likely be packing on extra weight. This plateau weight loss idea just does not apply with the Master Cleanse.
Hopefully Pepe will post his weight loss FAQ's again today. Reading that will hopefully help you to understand.