The excel add-in is great for loading lots of invoice lines and invoice journal lines.

It should be easy to offset a vendor invoice to a project using the excel add-in. (eg it shouldn't require ISV development)

It seems like most of the groundwork for this was done even prior to D365:

https://dynamicsax-fico.com/2015/08/22/excel-add-in-enhancements-2/

Can this be added into the core product?