No reason to defoliate.
And, in general, rarely a good reason to do it. Removing leaves doesn't shift resources or help the plant focus on flower - just the opposite actually. You are remving surface area for co2 absorbption, so it's reducing your limiting factor, that alone is reason to avoid it at all costs.
pruning off growth very selectively can have some advantages, but never blindly remove 33% of the leaves. Just throwing out the fertilizer you fed it and was stored. making the plant more susceptible to nute fluctuations etc etc.. it's just a horrible idea in almost every way with absolutely no benefits.
Not overcrowding canopy will avoid congestion-related issues. Simple as that.