I think there are a million theories on trimming plants, I've seen plants with all the vegetation 2ft or more from the bottom removed and they develop a series of branches that turn into full buds.

My theory(or at least I'm going to try this) is that during my last two harvests I've noticed the bottom most and inner most branching had the least amount of bud material and what was there was loose, smoked ok but my thoughts are if the plant doesnt' have to waste energy on lower level branches/buds then it can put more effort into the top branches. The seedlings I have now that are over two feet tall I've already removed evrything from the soil to a foot up the stalk and haven't noticed any detriment to the plant and in fact they are growing faster then I probably have room for right now.