Generic FTP - CSV file customization

We have implemented the Generic FTP to use for shipping orders. There are a few field changes and additions we would like to make to the default CSV file.

In the implementation guide: https://help.directscale.com/hc/en-us/articles/360050652814-Downloading-and-Uploading-Files-to-and-from-DirectScale

It shows this in the default file section:

If you change the order of HEADERS be sure to update the excel / CSV portions.
        private readonly List<string> _headers = new List<string>

There does not appear to be a hook created to allow this file to be modified. Would be great to have if possible!