> What about when the amount on a debit is higher that what Balanced, the network, or the bank support?

We don't have any behavior specified in this case, and as I mentioned before, I didn't even know this was a thing.

> Then why specify that it's a 409 vs. 400 vs. 402? They're unique values.

Right, so you specify which one comes back. Like we do here.

> What if they copy/paste from another error and include the wrong error message?

Then.... they'll have a bug? I'm sorry, I must be seriously misunderstanding what your point is.