[tomnipotent]

> This is why my company has custom applications that talk to the ERP for certain departments.

This is the best approach. Inventory is a great example of something that is both very important to an ERP and needs to be modeled impeccably if you want accurate costs (think license plate numbers tracked back to manufacturing), but at the same time you sure as hell don't want your ERP to be the "system of record" for operational systems.

It was a very humbling experience working with accounting and finance to close the books and update forecasts.