Asif2000, if you want to avoid the confusion, you can just use your US passport and NICOP to enter Pakistan and not use your Pakistani passport at all. I have several dual citizen friends who do this regularly without any problems.
Departure from US: Check-in with your US passport. If airline asks how you intend to enter Pakistan, show them your NICOP which has the words [Holder] "is entitled visa free entry into Pakistan".
Arrival in Pakistan: Show your US passport and NICOP.
Departure from Pakistan: Show your US passport (and NICOP) if they ask for it.
Arrival in US: Show your US passport.
Some relevant excerpts from the NADRA website about NICOP:
"The NADRA Ordinance envisages issuance of NICOP to Pakistani workers, emigrants, citizens, or Pakistanis holding dual nationality..."
"A valid card issued to a non-resident citizen shall be the conclusive proof of his being a citizen of Pakistan..."
DO: Los Angeles, CA
06/26/04: Married to USC
11/03/04: Resident since (EB3)
08/07/07: Mailed to CSC (3 years - 88 days)
08/13/07: Application received (Certified Mail)
10/25/07: Check cashed
11/21/07: NOA received
11/24/07: FP Notice received (for 12/19/07)
12/19/07: FP Date
06/19/08: Interview Letter received
08/27/08: Interview date (Approved)
09/08/08: Naturalization Oath (N-445) received
09/26/08: Oath Ceremony (LA Sports Arena)