Advance Parole Mailing question.

So I sent in my application for my Advance Parole last week, to the address listed on the site:

USCIS Phoenix Lockbox

U.S. Postal Service (USPS) deliveries:

USCIS
PO Box 21281
Phoenix, AZ 85036

However, when I checked the tracking number on USPS, I got the message :

Your item was delivered at 12:33 pm on June 30, 2016 in PHOENIX, AZ 85034.

Is this normal? Does anyone else with Advance Parole experience know?

Good question. I sent my AP to Chicago.

Did you do signature confirmation?

No I didn't. It's a POBox so I didn't think it was required.

Signature is never required. What's the issue? It was delivered successfully. Are you worried the zip code is different?