[ethbr0]

I don't have enough fingers to count the times I was doing automation in healthcare, implemented the process to spec, and then had a bunch of test cases flagged as failing.

Turns out, for large known counterparties, there are indeed de facto processes that incorporate each party's eccentricities and are "known" on the floor (processors typically have long tenures in their jobs) but unknown above a certain level of management.

E.g. a large children's hospital that reliably spit out misformatted requests to the local payer, but which the payer papered over on their side by converting them to payable requests (naughty, but kept them from bouncing back and requiring resubmission)... and had been doing so for 10+ years.