Address assignment doesn't always go as expected. Error codes don't always make sense, and output addresses can appear to be completely wrong. These are the types of questions we see frequently in support. Fortunately, almost all the tools available to support engineers are built into the software for end users, too.
The links above provide good information on these different utilities.
Indicator Codes
If an address assigns without an error code, that is the addressed assigned fully, but the output is unexpected, the next indicator to consider would be the status code. The AP.Stat_Code (jobfile) and ACE_STAT_CODE (Library) components will post a 6-character status code whether the address is assigned or not (i.e, S80000).
See the Quick Reference for Views and Job-File Products (pg 68) or the Quick Reference for Library Products for a complete list of Status codes.
The next step depends a lot on what code the address received. Did ACE append data, did it change data? Which part of the address was affected? Last line, secondary, street name?
Last Line
If the issue appears to be with a ZIP code, you might want to perform a last line lookup using ShowL and see if the zip was a Unique Zip Code, as special CASS rules apply to those.
If a city or state was changed, or wasn't changed and you expected it to be, try searching the Knowledge Base for the issue. For instance "ACE changed city" or "city abbreviation ACE". There are special instances when ACE can and cannot, per CASS rules, make changes to the last line.
Address Line
Moving up to the address line, there are a number of things to consider. How was the secondary address handled, is it a valid secondary? Was there a SuiteLink match that would cause the secondary data to change? Was the "secondary" data output as secondary data or put into a Remainder field?
You can use ShowA to investigate the valid primary ranges for a given street. It's also useful for checking secondary data and matching ZIP+4s.
Sometimes, a streetname will unexpectedly change. It can appear that ACE converted an address to a completely different street. In this instance, it's possible that a LACSLink conversion was made. See this KBA for more information on when a LACSLink lookup will be performed. Check the AP.LACSCODE field for a T/F indicator on whether or not the address needed to be changed.
Another time ACE might change the streetname is in the case of a streetname alias. These can be confirmed using ShowA, or you can output the APA.Type field, which will return one of seven codes detailing the alias status of an address. ACE does have an option in the Standardization Options to set alias addresses to convert or preserve, (Address Line Alias)
DPV
AP.DPV_Footnote and AP.DPV_NoStat can tell you things about the address assignment, the vacancy of a property, whether it's a mail drop, and some other notes on the deliverability. These two fields are a good place to check if you're receiving an unexpected undeliverable status.
Bad Data
ACE does a pretty good of interpreting junk data, whether it's extraneous secondary data, order numbers being included in address lines, or correcting misspelled words. If and address line is being returned with extra data which is causing the address to fail, first check the definition (def) and format (fmt) files to make sure the address components are being correctly passed to the software. QuickACE will also give an indication of how ACE parsed the various address pieces, and might show that, for instance, ACE is attemping to match a firm name as secondary address information.
USPS Changes
Keep in mind that the USPS directories can be slow to make changes. The addition of more apartment units, for example, might show up in the next release of directories. See here. Conversely, customers can sometimes be unaware that the USPS or their local Post Office has made changes to a street, subdivision, or even entire zip codes. If you suspect the issue is with data accuracy in the directories, check with the local PO or contact the AMS department of the USPS.
Sometimes an address will assign, or appear to assign, on the USPS webpage, but will be returned as undeliverable by ACE. Since there is no one method to determine correctness, this type of discrepancy usually ends up being a he-said she-said kind of thing. This KBA gives some insight into the differences between SAP's ACE product and the USPS' webpage: 1183566 - Comparing address lookup results to USPS Web site
https://bosap-support.wdf.sap.corp/sap/support/notes/1183566
