Address to send N400 Application...

[JoRu16 7]

Hello I am almost done preparing my N400 application but got confused over something

I'm thinking of using USPS Priority Mail Express delivery to send my N400.
I live in Florida so USCIS instructs these 2 addresses:

USCIS
P.O. Box 660060
Dallas, TX 75266

USCIS
Attn: N-400
2501 S State Hwy 121 Business
Suite 400
Lewisville, TX 75067

Does that mean I should still use the second address? Or is the second address meant only for FedEx, UPS, etc. while all USPS mail should be mailed to their PO box address?
Because In the USCIS M-476 Guide, it says that "USCIS, Attn: N-400, 2501 State Hwy 121 Business, Suite 400, Lewisville, TZ 75067" is for Private courrier ( NON-USPS) Deliveries.
BUT on the N-400 page on their website its for Express mail or courier deliveries. So which address should I send it to?

It's a pretty dumb question, but for some reason I'm beginning to get nervous over every little detail.

Thanks in advance.

[Nana098 18]

I have the same question:(

[DC85 113]

I read somewhere that some people who used the ST. Address with USPS express for their packages, the package got diverted to the pobox. I hope you get answers from members with recent experience.

Personally , when I will file after 3 months I will send it with fedex it's around $ 30. But you get reliable tracking and good service.