請教PJIAN及各位專家-After Service Request

本人的情況是
EB2, NSC, Priority date 01/28/05
I-485 received date 06/29/07

去年10月份I-485 RFE.說是60天後等消息,無果.

上個月底file service Request, 半個月後收到他們的一封信, 寫到:

Based on your request we researched the status of this case. WE are actively processing this case. However, we have to perform additional review on this case and this has caused a longer processing time. If you do not receive a decision or other notice of action from us within 4 months of this letter, pleas call customer service at the number provided below.....

現在時間又過去3個月了, 請問NSC 會按照信上寫4個月內給回複,還是說不一定呢?

謝謝!