My wife's EAD application experience

My wife's EAD application is pending at VSC for more than 4 months now. On 91st day (Which happened to be a Wednesday), we reached Arlington office at 1.45pm. They asked us to wait in a room, after a while someone picked up her receipt and gave her a form to fill out. After 30 minutes they asked her to wait in another room after verifying the payment info. She was done by 3.15pm, so I should say it was a painless and quick procedure. She was issued EAD valid for one year. I got a feeling that they are looking for only three things, A proof of eligibility (I-485 receipt notice in our case), a proof of payment ( Online receipt in our case) and if the case is more than 90 days old.