I don't believe I misunderstood the print in North U sail Trim book, but I'll re-read tonight. Thank you Sailormon6. I also found the "flattened" sails to be a bit contradictory. Seems like bearing off 5-10 degrees would be better than blading out the sails. I'll re-type the section where it says that it may help.
The part that I think is misunderstood is that people tend to read that article, and then they go out on their boat and trim their sails flat in light air, and think that their sails are trimmed optimally. It isn't that simple. I don't believe the author of that book meant to imply that we should forget everything we know about aerodynamics and sail trim, and just trim our sails flat in light air. I think he meant to say that we often trim our sails for the conditions at the start of a race, and then leave them essentially that way throughout the race. I think he's saying that most of us tend to create too much draft in our sails, and, as our boatspeed and windspeed increase, we tend to be too slow to respond to those changes with appropriate changes in sail trim. To sail well in very light air, we have to increase the draft of our sails beyond our normal sail trim, but, to optimize our sail trim, we should think in terms of creating a little less
draft in our sails than has been our usual practice in the past, and, as the windspeed and boatspeed increase, we need to begin to flatten the shape of our sails a little sooner
than we thought necessary in the past. In short, I don't think the idea of trimming the sails flatter in light air represents revolutionary thinking that supersedes all we thought we knew about sail trim. I think it's simply intended to get us thinking about it differently. It isn't a difference in principle, but a difference in degree.