Body fat % is m uch more important then the scale. Throw the scale out the window and focus on toning.

There are many reasons why having more lean mass is good.
1. Muscle has better circulation then fat, this means you burn more calories even when sitting on your tush doing nothing.
2. Improved circulation also means less apperence of cellulite.
3. Muscle takes up less room. A pound of muscle is much more dense then a pound of fat, so you end up smaller at the same weight. Working out regularly can mean the difference between two dress sizes at the same weight.
4. Having a healthy body fat and lean weight means more strength and endurance. Dropping body fat to low, or going into starvation where your body starts to eat your lean mass for protien will probably make you feel like crud, not to mention have other health consequenses.

Shoot for a healthy body fat %, not a number you came up with off a table or out of the blue. The weight height tables are based on averages and can be way off for many people. To get down to what many of them say is a healthy lower weight for me would require droping down to almost 0% body fat, basicaly dead.

If you have 98 pounds lean weight, then a reasonable goal weight for you would be 122.5 pounds (20% BF) to 132 (26% BF)

For women 10-30 years old 20-26% body fat is considered healthy. Most professional athletes are 15-18% when in compatition. I think one at 15% said in an interview they no longer menstrated and had some other side effects related to the hormone side effects of getting that low (She was a gladiator on that old TV show)