fx conversion consistency audit derived

{
  "input": {
    "body": {
      "policy": {
        "rounding": "half_up",
        "require_one_rate_per_pair": true
      },
      "conversions": [
        {
          "id": "FX-1",
          "on": "2026-09-30",
          "rate": "0.655",
          "to_amount": "655.00",
          "from_amount": "1000.00",
          "to_currency": "USD",
          "from_currency": "AUD"
        },
        {
          "id": "FX-2",
          "on": "2026-09-30",
          "rate": "0.657",
          "to_amount": "328.50",
          "from_amount": "500.00",
          "to_currency": "USD",
          "from_currency": "AUD"
        },
        {
          "id": "FX-3",
          "on": "2026-09-30",
          "rate": "0.655",
          "to_amount": "65.49",
          "from_amount": "100.00",
          "to_currency": "USD",
          "from_currency": "AUD"
        },
        {
          "id": "FX-4",
          "on": "2026-09-30",
          "rate": "96.505",
          "to_amount": "9650.50",
          "from_amount": "100.00",
          "to_currency": "JPY",
          "from_currency": "AUD"
        }
      ]
    },
    "type": "http",
    "method": "POST",
    "bodyType": "json"
  },
  "output": {
    "type": "json",
    "example": {
      "limits": {
        "maxEntries": 20000,
        "maxAccounts": 5000,
        "maxFindings": 500,
        "maxLinesPerEntry": 500,
        "maxStatementLines": 20000
      },
      "passed": false,
      "complete": true,
      "findings": [
        {
          "code": "CONVERTED_AMOUNT_DISAGREES",
          "detail": "FX-3 converts 100 AUD at 0.655 to 65.49 USD, and the product rounded to 2 place(s) under half_up is 65.5, out by exactly -0.01.",
          "conversion": "FX-3"
        },
        {
          "code": "CONVERTED_AMOUNT_DISAGREES",
          "detail": "FX-4 converts 100 AUD at 96.505 to 9650.5 JPY, and the product rounded to 0 place(s) under half_up is 9651, out by exactly -0.5.",
          "conversion": "FX-4"
        },
        {
          "code": "CONVERTED_AMOUNT_TOO_PRECISE",
          "detail": "FX-4 produces 9650.5 JPY, which needs 1 decimal place(s) and that currency has 0.",
          "conversion": "FX-4"
        }
      ],
      "consistent": false,
      "pair_count": 2,
      "request_id": "example-request",
      "service_id": "fx_conversion_consistency_audit",
      "assumptions": [
        "The converted amount is the exact product rounded once to the target currency minor unit under the stated mode, which is the only computation that can be checked without knowing the source system.",
        "A difference is reported with its exact size, because one unit is a rounding choice and a thousand is a wrong rate, and a verdict alone cannot tell those apart.",
        "Two rates for one pair on one date is reported, since it means two sources and whichever figure a report quotes depends on which conversion it happened to read."
      ],
      "conversions": [
        {
          "id": "FX-1",
          "on": "2026-09-30",
          "pair": "AUD/USD",
          "rate": "0.655",
          "to_amount": "655",
          "from_amount": "1000"
        },
        {
          "id": "FX-2",
          "on": "2026-09-30",
          "pair": "AUD/USD",
          "rate": "0.657",
          "to_amount": "328.5",
          "from_amount": "500"
        },
        {
          "id": "FX-3",
          "on": "2026-09-30",
          "pair": "AUD/USD",
          "rate": "0.655",
          "to_amount": "65.49",
          "from_amount": "100"
        }
      ],
      "limitations": [
        "Whether the amounts supplied follow from the rates supplied. Not accounting advice and not a valuation: whether a rate is the right rate for a date, a purpose or a standard is outside this.",
        "consistent is true only when every conversion followed from its rate and every rate was consistent across its pair."
      ],
      "observed_at": "2026-10-02T00:00:00.000Z",
      "not_examined": [],
      "finding_count": 4,
      "rounding_mode": "half_up",
      "service_version": "1.0.0",
      "conversion_count": 4,
      "findings_by_code": {
        "CONVERTED_AMOUNT_DISAGREES": 2,
        "SEVERAL_RATES_FOR_ONE_PAIR": 1,
        "CONVERTED_AMOUNT_TOO_PRECISE": 1
      },
      "one_rate_per_pair_required": true
    }
  }
}