In some major US cities, an extended form of the five digit ZIP code is used to further localise an address. It seems in my experimentation this week in Seattle, that a number of merchants use this extended code in their payment details.
Unfortunately whatever Mondo is using for address lookup doesn’t like the format. For example one transaction contained the address of “Seattle, 981012108, United States”, but this comes up with some ‘middle of USA’ location. I suspect if you detect the ZIP code format (all numeric, either 5/9 characters), and in the 9 char case, hyphenate it, e.g. 98101-2108, this will result in a correct location lookup and save you many many “this location is incorrect” reports!