You are correct in saying that autos can be grown under any light cycle but yield is directly proportionate to the amount of light you give the plants.
That is incorrect. Maturity is based on the trichomes. When the trichomes are amber that is the THC breaking down into CBD. If the trichs are amber and you let them go you are degrading the THC which ruins the weed.
What makes sense to me is that whether you push or pull you are still putting the same amount of air through the same amount of charcoal. Also the "kid" at the counter was a retired botany professor at UMASS and just from my limited time dealing with you I feel that I will go with his word over...