Hi Greg,
Many of the Prince Georges casino organizations moved their operations from one place to another for various reasons. I picked up my CIPAA chips at a fire station casino located in and named Oxon Hill. It is possible that Jack picked up his in Ft. Washington if the CIPAA operated there at some time. Another possibility is that since Ft. Washington is next to Oxon Hill, the fire hall in Oxon Hill may be served by the Ft. Washington post office and use that name in their address.
Best regards,
Tom in slab free Virginia

ps Some of the CIPAA $5 chips are mistakenly printed with "CIPPAA"