There's a disconnect in the name check in these cases. What happens is when the original application is filed, the child isn't yet 14, so they don't request a name check from the FBI. Now they finally get around to looking at your case and notice that the child is over 14 (our son was 13 and by the time they picked up our case, he was 16) and that the name check hasn't come back yet from the FBI. So they sit and wait, and wait, and wait...totally unaware that the name check has never been requested in the first place. (that would just take too much mental power to figure out). You can send in an status request to the FBI, but I hear the FBI is taking about 5 months to reply to any email inquiries. (phone inquiries are no longer accepted)
It's been about 3 months for my son since we were all approved and we're still waiting. I've phoned and faxed. (so has my lawyer). I've explained to them specifically what the issue is. So we'll see if anything happens. I heard that the service centers (ie. TX, VT, CA) can't request a name check a second time. It has to be forwarded to the national center where they will eventually get around to it. Yep, I know, they haven't even requeted it in the first place, but remember, we're talking about the USCIS here and if it requires common sense, it's not going to happen.
Best of luck and regards
Rav