Hi Joshi:
First of all, I would suggest that you not take what the National Customer Service says as absolute, nor should you rely on the information on the receipt notice or the online status because these are generic guidelines and do not and cannot account for each individual case. They are approximations at best and should be treated that way--as approximate timetables.
Now, if the immigration information officer told you the petition was approved, the online case status would have been updated to reflect this as well. If it hasn't been, then it's probably not yet approved. If you are working with an attorney and the attorney has a copy of the attorney representative form on file with the USCIS, then the petition, once approved, will be sent to the attorney so he/she will know when that happens. If you think that the Immigration Information officers were correct, call again and get their name and inquire as to why you have not yet received the approval notice if the case was approved 4.5 months ago.
Although it is true that some petitions are pulled out of turn and processed quicker than others, that is not the rule but an exception to the rule. THose people should consider themselves lucky, but it is not a precedent for others in the queue. ALso, some Service Centers process petitions on different timetables, so make sure that your friend's was processed by the same service center. And finally, each petition is adjudicated on its own merits so what happened to your friend or anyone else you may know is completely irrelevant to your situation, since your application is reviewed on its own.
if you are gettting contradictory information from different sources, ask your attorney to follow up with the service center on your behalf. after all, that is what they are getting paid for by you or by the company--to represent you in this matter.