Birchstreet AP Interface

Hello - 

We are looking at creating an SFTP interface between Birchstreet and Acumatica. It is a pretty straight forward interface, that would be sending vendor and payment information outbound to the SFTP, for Birchstreet to pick up, and Birchstreet would be sending AP, (Bills with file attachments) to Acumatica. 

I know we can run import scenarios with AP Bills, and this seems pretty straight forward, but our Acumatica host SWK, quoted us at 100-150 hours of coding to get this done. This seems very high for such a simple interface. Does any other Acumatica user have an existing interface with Birchstreet?

Thanks!