I have only anecdotal data, but am wondering if others have observed this, before I set out to test it proper like.
This is mostly in reference to lagers, but I've noticed in the hoppier beers as well.
It seems to me that if I add my aroma hops at 5 min. to flameout, while I do get less aroma than if I add at flameout, what aroma I do get seems to last longer once packaged. I'm thinking there is some reaction that is occurring that somehow stabilizes the aroma compounds (kinda like what people say about first wort hopping and hop flavor lasting through the boil)