i had an infopass appointment. my i-551 was extended for 6 months only. do they not usually extend it for 12 months or more? i wonder why it is 6 months in my case.

The I-751 is still pending and you should have an answer shortly, so 6 months in not unreasonable.

http://www.visajourney.com/timeline/profile.php?id=10500 (Not enough for removal of conditions)

Dude, how do you know that he "should have an answer shortly"? You don't.

If you actually participated in this forum instead of randomly swooping in like this, you might know that some cases at NSC have been pending for over a year, with absolutely no indication that they will be approved anytime soon. Indeed, someone just mentioned that they were told at an InfoPass that it might be at least 18 months total before their NSC I-751 is approved. Which means the OP will have to go back and get another stamp.

Also, this is the second time in two days I've seen you swoop in here with a non-responsive post and tout your timeline fetish. Here's a thought: Why forget the timeline bit for a second and try actually answering the OP's question if you can?

And the answer to the question "do they not usually extend it for 12 months or more?" is: They should, because there is a CIS policy memorandum specifically instructing field offices to issue I-551 stamps for 12 months. Unfortunately, some field offices or officers in those offices are either unaware of the memo or ignore it. The best thing to do is to bring along the memo.

Not really. If he had to make an Infopass appointment to get an extension stamp,
his 1-year extension letter had already expired, which means his case had already
been pending for over a year. A year plus six months of the extension stamp -
and there's your 18 months. Which means the OP will probably NOT have to go back
and get another stamp.

I have to side with James on this one. He mentioned that the 18 months were given as a minimum time, at least was emphasized. Given the current inactivity of certain service centers, a further delay seems not excluded at all. More important, the memo mentioned explicitely 12 months as stamp duration - what does the USCIS lose by giving the 12 months? On the other hand, a shorter stamp leads to uncertainty if and when you have to go again to get another stamp. If the USCIS causes delays, then it should not put not more work and hassle on those whose applications are delayed.

I went with the memo to my infopass appointment, and I was prepared to argue for 12 months and, if necessary, speak to a supervisor. The memo is binding for the USCIS officers if not repealed. Fortunately, my stamp was for 12 months without discussion.

18 months is rather unusual, isn't it?

Sure it happens to *some* people, but most people get approved within 6-12 months.

The OP didn't, so the USCIS gave him another 6 months, probably assuming he won't need more than that - most people don't.

That's all I'm saying.