NSC filling address, pls help

我交I140 and I485 concurrent， 在NSC 网页招到两个地址：第一个是邮寄地址：U. S. Department of Homeland Security
U. S. Citizenship and Immigration Service
Nebraska Service Center
P.O. Box 87485
Lincoln, NE 68501-7485
第二个是说如果是If using overnight delivery by any private service provider, send your package to:
USCIS
Nebraska Service Center
850 S Street
P.O. Box XXXX
Lincoln, NE 68508
我要用Fedex overnight, 请问寄过的朋友，　你们用的哪个地址呀，谢谢大家了