[AccessD] OT: US Zip codes

All,
 
 A while back, a link was posted on the list for a geo database containing
all US Zip codes, which was part of a web site.
 
 Recently with a client, I had reason to compare this list with one provided
by CCH for CA and OH for sales tax purposes.  When I compared the two, I
found 231 zips that existed in the Geo database that were not in the CCH
database.  Checking the web, I found a few web sites saying these were
valid, but after contacting CCH, they pointed out that they are not
according to the US Post Office.
 
 One such is:
 
'43989','Short Creek','OH','40.296490','-81.102502',-5,1,'us'
 
 We discovered this when my client had a customer place an order using this
zip and it didn't calculate sales tax.   According to the US Post office and
UPS, it's not a valid zip.  Yet the city name the customer entered matches
the geo database entry and a couple of sites out on the web (i.e.
www.uszips.com <http://www.uszips.com/> )
 
 Anyone worked with US zip codes and might have an idea of where the
disconnect is or why?  I'm left scratching my head between a customer that
believes they are using a valid zip and USPS and UPS saying it's not.
 
Jim.