I-485 Case Transfer to Local office- San Francisco

[kisha]

Company A:
My GC was sponsored by Company A.
LC was applied in June2002.
My I-140, I-485 was applied in 2004
I-140 got approved in 2004.
After getting my EAD card,AP and after 180 days,I left company A and moved to Company B on W2(consultant) in San Francisco and after 10 months I moved to Company C on W2 in San Francisco. Recently
I got a letter that my case has been transferred to Local office in San Francisco for faster processing.

"This is to advise you that in order to speed processing we have transferred the above case to the following INS office for processing. ....

That office will notify you of the decision made on the application or petition. Any further inquiries should me made to that office"


I had not filed my AC21 yet. Do I need to file my Ac21?.. I am working on W2 and I don't have any offs
in my payroll after moving from company A till now. I am still working for
company C(consultant) on W2.


I have a few Questions.

1. Do I need to apply for AC21?
2. applying for Ac21, is it mandatory?
3. Any other reason for case getting transferred to local office?
4. Will i be in trouble if i don't apply for AC21?
5. any idea how long it will take to get I-485 approved.

I would appreciate your response on this.

Thanks.