I guess you know more about it that my pal John Palmer. In any case late hopping, in the last 30 minutes or less, will contribute to both flavor and aroma. In my experience I get less flavor and more aroma at 15 minutes or less. My beers consistently have a ton of flavor and I do additions at 30 to 15 minutes for flavor, 15-0 for aroma. I also dry hop in the fermenter and will dry hop in the keg to get even more aromatics. YMMV.
Hops will contribute less and less flavor the longer they are boiled.
Try this 1 gallon experiment - make 2 batches, and with one add the flavor hops at 40 minutes, with the other add them at 15 minutes. Because the 40 minute hop boil will add more bittering than the 15 minute boil, you will have to cut back a little on the 60 minute bittering addition.
You will get hardly any hop aroma (maybe 0) with a 15 minute boil.
A 15 minute boil is used for flavoring hop additions for a reason. It contributes most of its flavor during that time (15 minutes is used as an easy to remember round number. isn't a hard number it can vary, maybe 18 minutes is optimal, maybe 20, but 15 is a good estimate).
If you use a lot of flavor hops at 30 minutes, and no bittering additions, then of course the quantity will make up for the amount of flavor lost.
If a brewer uses 4 ounces of flavor hops at 30 minutes then I'd expect they would get more flavor than someone who uses one ounce at 15 minutes.
It's a curve and hops flavor drops beyond a certain point. In fact, if it didn't you would see more people using no bittering addition, and isntead using more flavor hops at 30-40 minutes.