Interesting. I've found the most economic way to feed hay 24/7 to be slow hay feeders, which you can use with small or large bales (as long as you don't mind dragging the hay off the large bales to load up the slow hay feeder). Since I started using slow hay feeders there is no waste at all.
Thanks for posting that article, very interesting. I feed from a ring type feeder and I know there's a lot of waste if I give them too much hay/haylage per feed.