Your hunch is correct, total and utter nonsense, for exactly the reasons you listed, they are the plants main and most effecient energy producers and the bigger the leaf the more effecient it become, so lots of huge fan leaves=lots of huge buds.lol. last harvest did you cut off any leaves during flower(or veg i guess, but flower is more important) because they looked like they were yellowing and starting to die?im sorry if u already know this but i figured i'd say it just in case-, if your later(and some will start halfway,but just start, not full blown like towards the end)in flowering your plant will take all the energy its stored in its leaves for all that time and put it into the buds, so dont remove anything that doesnt come off with a gentle tug. that counts for later in vegging too, the oldest fan leaves will reach the end and the plant will decide to get rid of the leaf so it will first suck out what it wants in the leaf, so cutting leaves just throws that energy away.