Hunger and calorie intake were inversely proportional for me when I was fat. If I wasn't particularly hungry, but was bored, 5000 calories could disappear in an instant. If I was starving, I usually couldn't make it past 2000. One thing I do remember well was that I never ate breakfast, would have a big lunch (3-4k calories) and a bigger dinner (5-6k).
I'm also curious what the heck these weight loss maintainers are doing to require so few calories. To maintain me 140 pound loss, I need about 3500-4k calories a day depending on the intensity of my training. Sure, I'm a bigger guy than most of their subjects, but really, 1800 still seems like a nice sized dinner to me...
As long as I'm ranting, the biggest issue seems to be the idea that walking for an hour a day is "extremely active". I get 30-40 minutes of walking in daily just going from one building to another on campus. When I'm in Europe for work, its not uncommon for 90 minutes a day. (Which may be why no matter how much I eat over there, I still drop 5-7 pounds a week for the first couple weeks).
In conclusion, people need to look at the idea of health differently. The goal needs to be to keep excess fat off rather than keeping weight down. I have less fat at 245 after 18 months of training than I did at 215, my lowest weight after committing to lose fat. Calories aren't the enemy, sedentary lifestyle and excessive intake is.