Yes i have a possible explanation. It's funny you made this comment because for many years i was stuggling and having subpar yields. In my case (which may also be yours), i was growing a very stout and broad-leafed indica (Querkle). It's leaves would literally shade every branch accept its colas when left untopped. I also had them packed in a SOG and my canopy was way too dense, which only amplified my problems. I basically would end up cutting off the lower 50% of the plant and cutting many fan leaves in half to allow light to the remaining budsites. This was a problem for many reasons. Tons of wasted veg time, slowed photosynthesis because of all the bottom suckers, intense pruning (which sometimes *GASP* lead to shock). For all these reasons i tried growing much smaller plants. I have found that the smaller plants (with a properly managed canopy) yield heavier and higher quality nugs. The conclusion i have come to is that although the plant has fewer branches (and budsites) those fewer budsites are recieving intense, unshaded light. Also, the plant is able to focus ALL of its energy on JUST those branches (and buds), and doesn't have to waste energy trying to keep the bottom blood suckers alive.
Being said, I have had better results using the same wattage and space and plant numbers growing smaller plants rather than larger, all while saving myself a couple of weeks in veg time. The result is fewer buds, but much larger, fuller, denser, resin-ier, and faster to mature.
Anyone whos grown querkle or urkle knows how painfully slow she grows in veg, so cutting your veg time in half, while maintaining the same (or better) yield is quite a feat.
Although this all seems pretty obvious, some people still insist on over vegging and wonder why they arent getting good yields. It's particulary important to know your strain and its growth patterns, and how to manage your plant and canopy. Many factors come into play when considering plant height, width etc, but this is a very important aspect to growing which is often overlooked.
I cannot stress enough how important it is to know your strain.
Hope this helps a little?