Party Postal Addresses V2 entity not importing field

I have extended the DirPartyLocationPostalAddressV2Entity to include a custom field which is added to the address. We need to import this field for go live as there a lot of them and manually doing it would be painful.

I have added one field called Manufacturer's Rep. After adding it to the staging table and entity, I generated the source mapping through the Data Management > Data Entities > Modify Target Mapping screen and the Rep field shows as it should. In my import file there are all the necessary fields that it is looking for. I attempted to import it and it claimed to be successful. I went to check the contact address and it didn't fill it in. 

When we import into Customer Postal Addresses it fills in fine but for contacts (Customer contact) it doesn't.

What should I try to get this working? Am I missing a step that had been added into data entity changes for Version 10? We just recently upgraded.