I should let this lie as an explained joke is never funny, but I just can't.
USPS - Delivery Point:
(1) A single mailbox or other place to which mail is delivered. A street address does not necessarily represent a single delivery point because a street address such as one for an apartment building may have several delivery points. (2) A specific set of digits between 00 and 99 assigned to every address that is combined with the ZIP+4 code to provide a unique identifier for every delivery address. The DP is encoded within the POSTNET or Intelligent Mail barcode.
Interesting, the last/only time I had to write code to determine delivery points was very early in my career (IBM mainframe COBOL) when postnet barcodes were a new thing and it was always just the last two digits of the street address. I see in the current CASS technical guide that a record type H may have multiple delivery point. Learn something new every day. Thanks.
Edit. As an aside, I think current Microsoft word still calculates it that way when you "bookmark" and address and insert a barcode field. At least it doesn't seem to be sending a query out to the USPS.
USPS - Delivery Point: (1) A single mailbox or other place to which mail is delivered. A street address does not necessarily represent a single delivery point because a street address such as one for an apartment building may have several delivery points. (2) A specific set of digits between 00 and 99 assigned to every address that is combined with the ZIP+4 code to provide a unique identifier for every delivery address. The DP is encoded within the POSTNET or Intelligent Mail barcode.
https://about.usps.com/publications/pub32/pub32_terms.htm