I think you'll find "hard evidence" difficult to come by. It's my belief that most ideas that may show a worthwhile gain in yield are the ones that get documented. But since there is no "easily" discernible difference found between veg. light schedules, no one has bothered to do a real scientific research study. Most folks just go by the accepted guidelines and concentrate on maximizing other variables that make a larger difference over the course of the grow.
So, I also believe the choice is based more on energy savings than on raw results obtained by that choice.