What's the point of the invoice?  Typically we only see these with a plus and a minus line (totaling zero).

The client wants to record a monthly invoice for certain vendors, even if it is $0.  The import source file records include the header and line data on the same rows.

Import with a /C comment line with something like "Monthly Invoice"

Have a similar situation where importing in AR repetitive invoice entry and have a misc charge for a warranty but it's zero dollars. Don't really want to make it a comment. Is there something in the VI job that I can tweak to be able to import a misc charge no extension?

For the record, AP invoice entry does not allow /c fields ala SO and PO entry.  I enter AP invoices without any line values as a record of filing taxes at month end.  I enter the invoice and use the header comment filed to record the filing confirmation number.  This provides a quick way to verify (at a later date) that the filing was completed.  I use the default gl account for the vendor, zero amount.  The header comment defaults to the line comment field.  I find this an ideal way to track.