Hi yes2003,
I am not sure, by this time if you have already completed the visit.
I live in Austin, I went to Houston INS about 2 months back. I had real bad experience meaning in terms of crowd. I reached the INS around 5:15AM, by that time already about 200 people were ahead of us. May be it is worth reaching there by 4.00AM so that you will be safe. Any how we were turned down saying that we need to go to San Antonio for our IEAD. So we were out by around 9.00AM