It depends how much longer the plant would take to finish after that 2 week flushing period.

Personally, I think 10 days is good enough when flushing, but I use organics. (I like them really clean before chopping)

Also,
You can always look into a cleaning solution that you add into the water- they do work.
They also take 3-4 days as opposed to the 7-12 days without.
I use clearex myself.