I'm pretty close to the 100 pound mark....I still have saggy spot in my tummy but it's slowly getting smaller (I've been weight training for about 6 months now...). I doubt if it will ever completely go away short of chopping it off - but it's a hecka lot better looking than it was 90 pounds ago.
It goes away when I'm horizontal.
And a pair of jeans can pretty much hold it in now even when I'm vertical.