Replying your question:
We had our interview on Feb 28th and got our cards on Mar 9th. Check my profile for case details. The interview seemed like a formality. Our Attorney got there before us and had us checked in at the counter. My spouse had the interview scheduled right after mine but we had the interview together. It's a bit low tech how they call you for the interview. The Baltimore Office has a huge hall with two doors, one on each opposite end, far away from each other. The Officer will come out of one of the doors (you won't know which one) and call your name. Most of them don't use the PA system. So, you have to pay attention, especially with their pronunciation of the foreign names. We sat at one end at the beginning and them moved to the center aisle so that we can monitor both doors. Our interviewer came out on the right door, did not use the PA system but we responded quickly. We were taken to an Office, took oath, answered each item (first thru last page) on the 485 form. Office asked for my Employer verification letter and latest pay stubs. I showed the originals and gave the copies for the record. Officer asked if we have anything to add. I said No. Officer asked our attorney if their is anything to add. Attorney said No. The same repeated for my spouse. Interview was over in 25 mins. Officer had us wait outside as while taking copies of passport and EAD cards. At the end, we got the standard letter about waiting to hear from USCIS for 120 days. To our surprise, we got the approval letter by mail on Mar 5 which said the cards will be mailed or bio-metrics will be required within the next 90 days. We got call from Attorney that they have the cards 3 days later. Online case status was not updated after the interview. This has been a great forum to exchange information and learn the process better. Good luck all!!