take a look at my spectrum chart.. u have to consider these focal points, where the Photosynthetic curve meets with the rate of chlorophyl absorbtion, as opposed to the LED. 635nm is in the orange-red range of the spectrum.. The photosynthetic response curve is at its peak. This would be optimal for flowering because thats the stage where its photosynthetic response is at its highest.. the 470nm in the blue spectrum is optimal for the vegetative state, where its chloropyl absorption rate is at its peak, which is used to produce energy.. it'll need energy for flowering...