I processed a list with the following address:
324 10TH Ave Ste 285 Salt Lake Cty UT 84103
Notice the spelling on "Cty". It is quite obvious that it should be "City". Your address verification system successfully verified the address but didn't correct the spelling. What's going on?
The verified output for that address is:
324 10TH Ave Ste 285 Salt Lake Cty UT 84103-2892
But the "Cty" hasn't been changed. It looks strange to us as well. A quick check with the USPS documentation, as well as their website shows that the actual city in 84103 is Salt Lake City, but there are two additional acceptable spellings: "Salt Lake Cty" and "SLC." Knowing that, we don't correct the city name if it is "acceptable." If the city had been entered as "Salt Lake" it would have have been corrected to "Salt Lake City."
One further example of this occurs in ZIP Code 84604. The default city name is Provo. Sundance is also an acceptable city name. The two locations are 10 miles apart with no houses in between. Sundance is a resort town up in the mountains; Provo is down in the valley. No one living in Sundance would ever say that they live in Provo (even though the USPS says that they do) so for us to change the city to the default city of Provo would not make sense. It seems a little screwy but it does actually make sense (from a certain point of view).
Solutions: One of our customers needed to be able to accept input that was sometimes missing a ZIP Code but could also be missing city or state. They wanted to store only the "preferred" city name. Our initial suggestion to just submit and address validation request without a city because we would always add the preferred city. This worked for them most of the time, but sometimes they had invalid ZIP Codes or no zip code. The better solution that worked for them was to submit the address twice. The first time it was submitted normally to complete all the necessary data. The second time it was submitted without the city name. This causes our system to fill in the city name with the default city. Problem solved.