pt,
I did my second FP and thought will share my experience. My second FP notice was issued in 10 days after the expiration of my first FP (15 months).
Did go to North Dallas office before the date indicated on the FP notice as I did for the first FP. This time the folks there were very adamant about the date and sent me back.
I went to South Dallas a week later and they did my FP though they did saw the date and I had to talk to them. I just wanted to do at the earliest as I waited long enough.
INS site update that they received mine and wife's FP on May 14th, 2003.
Waiting since then for the good day.
Hope that helps and if you have a specific question, post it and I will reply if I know.