Here's my theory on defoliation.
The TLDR version is the more you defoliate, the more bud sites you promote, but the smaller those buds - and overall yield - will be. I've tried both ways, and the results match the theory.
Here's the reason why:
Plants will naturally defoliate themselves when they receive little or no light. We've all seen it. Lower leaves that receive no light turn yellow and die.
Stored nutrient and starches are removed from the leaf before it dies, and are transported to other parts of the plant where there is more light.
If you remove a perfectly healthy leaf, what have you just done? You've removed a source or stored energy and nutrient.
But you've also allowed light into the lower canopy which can be use for photosynthesis, right?
Not really.
Plants grow where there is light. But growth is not just limited to the amount of light available for photosynthesis. It is limited to gas exchange, moisture levels, molecular activity (warmth), nutrient availability etc. So growth is ultimately limited to root system volume and efficiency.
There is a balancing act between what the roots can supply (water, nutrient), and what the leaves can photosynthesise (using light and carbon dioxide).
When you remove leaves, you are not only removing stored energy, nutrient and moisture, you are removing areas of photosynthesis.
So the plant takes a backward step every time a leaf is removed without being able to recover that stored energy and nutrient, as well as losing a source of photosynthesis. It has to produce more leaves. Which is exactly what it does.
You need the chicken before the egg, so you can't have photosynthesis without leaves. And you can't have flowers without photosynthesis.
By defoliating, you divert resources away from flowering. You also divert growth from the upper part of the canopy to the lower part. The plant can only grow as fast as the roots and leaves allow, given a certain amount of light and warmth.
The upshot is, while you are promoting lower canopy growth, you are diverting it from the upper canopy which relies on those big old fan leaves for photosynthesis and stored moisture, nutrient and energy that would have been used for flowering growth.
If you had not defoliated, the lower canopy would have died off anyway, passing its stored energy and nutrient to other parts of the plant, where it would be used instead of having to draw additional resources from the roots.
All you've done is delayed growth by wasting and diverting resources that would have been used to promote growth on other parts of the plant (the upper canopy).
Try it one day, and I guarantee you'll see a difference in bud size and yields.