I belive in set point theory in terms of totally mass yes. However this controls hunger more than anything. The farther above this weight one gets the less of an appetite they have. Mine is 225-230, so now I'm having to force myself to eat. When one gets far below it, they become very hungry, all the time.
No, it's just that 23% is a bit of a sticky point for you right now. Its below average, and you were overweight, so your body may be a bit reluctant to drop more bodyfat. Adjust your diet and make some changes in your routine, suppliments etc that speed up metabolism and you'll start to see progress again.
Thanks for the compliment. Believe me, it means a lot coming from attractive women when they compliment my body (I blush sometimes in real life), because I was fat prior to my change in lifestyle. Its funny that I still blush even if I've been getting alot of them. At my last job, and at the gym I get them alot.