Calories - Need advice!

About me:
36 years old
4'9" tall
CW fluctuating between 107 and 109 since I joined
GW 98 (been here before, so I know I can do it, and K-A suggests UGW @ 93 lbs)

I'm fairly active. When I started on MFP, I had already gone back to the gym in April 2011 to lose weight and get in shape, but the scale had gone in the wrong direction, up from 108 (where I am now) to 115. In November 2011, I started training for two half marathons, one in January and one in February, thinking that would help me manage my weight, but no dice. When I joined MFP, I weighed about 111, and based on what I know I used to eat, I would guess that I was eating around 1800-2000 calories a day.

Using the Katch-McArdle formula, my BMI is around 1100 and my goal weight TDEE is around 1600 calories per day.

So I started cycling my calories, keeping them low on weekdays and spiking on weekends, averaging about 1600 calories a day. But that didn't work. I mean, I lost the initial few pounds, but I've been stalled ever since. I've cleaned up my diet immensely (my diary is open, feel free to look). I cooled off my running and weights routine starting in April, thinking I might be carrying water weight for muscle repair. I started getting more sleep and doing stress relief. I brought my average down to about 1440 calories per day. At first, I lost another pound, down to 106. A couple of weeks later, I was back to 108. I've been gaining and losing the same 3 pounds for four months.

According to all the calculations, I should be losing at least a half pound a week, which means I should be at 101 by now. But, like I said, I've been 108 pretty much since my third week on MFP. And I'm not doing anything drastically different than when I used to weigh 98 lbs -- other than that I've since developed severe food allergies.

When I joined MFP, I thought 1200 calories a day was the magic number, but there is a "eat more to weigh less" craze on MFP, so I ate more. Now I'm thinking that eating less to weigh less (ahem, common sense) is the way to go, but I'm not sure how much less. If half a pound a week is 1750 calories, and I currently eat 1440 calories a day, to drop 1750 calories a week would bring me down to 1190 calories a day. Not impossible, but... a little scary.

I'd love advice and support, ideally from people who have lost those "last ten pounds," and how you did it. Bro science is not really necessary, thanks.