I just got back from India 2 days ago using AP. I am no longer on H1-B. My port of entry was philadelphia.
Initially, our finger prints and photos were taken and sent to Secondary inspection.Usually anyone using AP to enter will be subject to secondary inspection. At the secondary inspection after verifying our AP , the officer put a seal saying AOS with a date on the AP and I-94. They will retain one copy of the AP and return one back to you. Passport and un-expired AP(both copies) was all that was needed.
When you first approach the Immigration officer let him know that you are using Advance Parole.
Surrender all your i-94s while leaving. Make a copy for your records (both sides).
I was also prepared with a letter from my employer stating that i am working as .... since ....... Just a 2 sentence employement letter from my HR and carrried copies of my recent pay stubs. Also kept my i-485 receipt letter and i-140 approval letters. All these are supporting documents. Its good to carry them if they inquire more.
The immigration officers were very friendly. No issues or concerns. Nothing to worry. i have changed jobs twice using my EAD now.
Word of advise. when talking to the immigration officer, keep your sentences short and to the point. Smile and greet when you meet. Try not using abreviations for example AP. Say 'Advance Parole'.
Used AC21 twice
Greened on 07/20/10