Hey filo6942,

Thank you for speaking up on this subject. I was starting to think I was stuck in a black hole of ignorance.

Again, this is a topic that should not have to be argued about. You can find the answer in a book! I reccomended one that is great to have around, virtually every glasshouse operator I know has this book on his shelf.
"Horticulture, Principals and Practice" by George Arquaah

....or so easy to prove with a simple experiment.

I am not advocating any perticular light schedule to anyone, I happen to use BOTH at the present time! It is what works best for you, in your particular situation. BUT don't tell me or others that it is detrimental to the plant unless YOU CAN OFFER PROOF.