Except that individual departments do bill each other internally. It's how major corporation accounting works.
The CFO & acct dept does not send a literal invoice to the IT department where the CTO has his own mini accounting staff handle the invoice and cut a check back to the CFO. When corporate counsel reviews a Terms of Agreement for the IT dept's web service API, they don't send an invoice for $400/hour for "legal services". Not dealing with thousands of such "transactions" as explicit costs is one of the reasons firms exists (so the theory goes.) Internal operations do not send purchase orders to each other. They don't remit checks to each other. Each sub department doesn't have their own sales team haggling internal prices & discounts with other department heads. Etc, etc. It's the external companies' interactions that have all those costlier transactions.
(Sorry sarcasm, spent too long working with ebXML a decade ago and occasionally watch history repeat itself - idea is to achieve "straight through processing" where invoices, tw and CS and so on are international standarss and digitised.
It's a nice pipe dream - but the goal is to make a cloud of 100 freelancers as efficient as a firm
I can't see it though
The invoicing and payment processing part is small compared to the other costs and risks of doing a deal.
Seems dubious I agree
Yes they do. I'm working for a fairly large company (several thousand employees) where projects often covers several business units on different physical locations and each department bill their hours to the next down the factory line.
For example my team seldom deal with external clients, however our sales man has to fight tooth and nail to protect our margin against other internal dep.