VERIFIED SOLUTION i

Which 'ADDRESS" file ZIP/ZIP+4 is used in the CSM-1168 Field Code for the "Entry Point - Actual / Delivery - Postal Code" in MailStream Plus

When you look in the USPS FAST 'ADDRESS' file for the LOCALE KEY and ZIP/ZIP+4 for an entry facility, there are three ZIP+4's given-

 FIELD                                         RELATIVE
 REFERENCE  FIELD                   LOGICAL    POSITION
 NUMBER     DESCRIPTION             LENGTH     FROM/THRU   CONTENT NOTES
 --------   -----------             -------    ---------   -------------

  5         DROP SITE DELIVERY ADDRESS
             ZIP+4 CODE               09       128  136

  6         DROP SITE PHYSICAL ADDRESS
             ZIP+4 CODE               09       225  233

  7         DROP SITE MAILING ADDRESS
             ZIP+4 CODE               09       322  330


Sometimes the three fields have the same ZIP/ZIP+4, but sometimes 2 agree and one is different, or sometimes all three are different.  For example here are a few SCF entry points that each have three different ZIP/ZIP+4s.  (Positions were moved in the data below to fit onto one line for each.)
                               Delivery 128 - 136        Physical 225 - 233    Mailing 322 - 330
DEX19355  SLEHIGH VALLEY                180208996                 180179005            180029997
DE004291  SGREENVILLE                   296073731                 296074609            296079510
DEY23078  STAMPA                        336305009                 336305012            336309997


The CSM-1168 Field Code Field Name is "Entry Point - Actual / Delivery - Postal Code", and the Mail.dat Specifications and the USPS Technical Notes say it is the "ZIP + 4 of building receiving the mail".  So the *Drop Site Delivery Address* ZIP/ZIP+4 from ADDRESS file positions 128-136 is what is used.
UPDATED:  August 10, 2017