Outcome Billing Error Taxonomyv1.1OCTOBER 2026

Seven ways an AI outcome invoice goes wrong

A public, versioned standard for classifying claimed AI outcomes against a contract, the buyer’s records and the buyer’s acceptance rules. Buyers audit against it. Vendors can pre-comply with it. The tests are deterministic: same inputs, same class, every time.

T1

Definitional drift

Floe action · Renewal lever
Definition
The vendor’s billable unit is broader than the buyer’s accepted unit. The outcome satisfies the contract as written but not the buyer’s acceptance rule.
Test
Outcome is contract-valid AND fails one or more buyer rules (duration, disposition, reopen window, human handoff, channel scope).
Evidence
Contract clause on the unit · vendor event · buyer system-of-record entry for the same outcome · the buyer rule that failed.
Example
A “resolved conversation” the customer reopened within 7 days. A “connect” under 30 seconds that reached voicemail.
Note
Not a billing error. Paid this period; repriced or redefined at renewal.
T2

Double counting

Floe action · Credit
Definition
One underlying outcome billed more than once, across channels, sessions, retries or reporting periods.
Test
Two or more billed events resolve to the same buyer-side record (contact, ticket, claim) inside the contract’s de-duplication window.
Evidence
The billed event IDs · the single buyer record they map to · the contract’s per-contact or per-period cap.
Example
The same contact dialed by voice and messaged by SMS, both billed as a connect. A ticket closed, reopened, and closed again, billed twice.
Note
Contract-invalid. Disputed on the invoice.
T3

Billed to minimums

Floe action · Credit or Renewal lever, by contract
Definition
Units invoiced against a contracted minimum or commitment rather than delivered, verified volume.
Test
Units invoiced exceed vendor events delivered in the period, with the difference charged to reach a minimum.
Grain
Invoice line.
Credit when
The contract does not support the charge: no committed minimum, an annual commitment applied monthly, a ramp or proration ignored, or shortfall priced above the contracted rate.
Lever when
The buyer committed to the minimum: the charge is valid, the buyer paid for units never delivered, and the commitment gets resized at renewal.
Evidence
Invoice line · vendor event count for the period · contract clauses on the minimum: commitment, period, ramp or proration, shortfall rate.
Example
1,500 connects invoiced in a month with 98,500 events, to reach a 100,000 floor.
Note
Shortfall units have no outcome behind them, so they are never counted under T1.
T4

List-rate true-ups

Floe action · Credit
Definition
A rate applied on the invoice that differs from the negotiated rate: list price, a lapsed discount, a tier threshold crossed late, or a true-up at the wrong rate.
Test
Invoiced unit rate ≠ contracted unit rate for the tier in force, with the tier set on the volume basis the contract names, or a true-up line is computed at a rate not in the order form.
Grain
Invoice line.
Amount
Credit = (invoiced rate − contracted rate) × units on the line not already credited under T2, T5, T6 or T7.
Evidence
Invoice rate per line · order form rate table · volume in the period.
Example
20,000 units at $0.88 on an $0.85 contract: 20,000 × $0.03 = $600. A true-up computed at list after a volume discount was agreed.
Note
Arithmetic, and the only finding that usually is.
T5

Duplicates & reversals

Floe action · Dispute
Definition
Events the vendor’s own log marks as retried, cancelled, reversed or failed that nonetheless appear on the invoice.
Test
A billed event has a later vendor event that negates it (reversal, cancel, retry-of), or the same vendor event ID appears twice.
Evidence
Vendor event and its negating event · invoice line · contract clause excluding reversed events.
Example
A connect followed two seconds later by a reversal event. An identical event ID billed in two consecutive invoices.
Note
Contract-invalid on the vendor’s own evidence. Disputed line by line.
T6

Contract-definition failure

Floe action · Credit
Definition
A billed outcome that does not meet the contract’s own definition of the billable unit.
Test
The outcome fails one or more terms of the contract’s outcome definition (duration, disposition, reopen window, human handoff, channel scope), on the vendor event or the buyer record.
Evidence
Contract clause defining the unit · vendor event · buyer system-of-record entry · the term that failed.
Example
The order form defines a resolution as closed with no human handoff; the ticket shows a transfer to an agent.
Note
Same rule types as T1. If the rule is in the contract, it is T6 and a credit. If it is only in the buyer’s standard, it is T1 and a renewal lever.
T7

Unmatched outcome

Floe action · Dispute
Definition
A billed outcome with no corresponding record in the buyer’s system of record.
Test
The billed event resolves to no buyer-side record (ticket, contact, call, claim) on the join key, inside the matching window.
Evidence
Billed event ID · the key and window searched · the empty result · contract clause on substantiation or audit rights.
Example
A “meeting booked” with no CRM or calendar event. A “resolved conversation” with no ticket.
Note
The vendor substantiates or credits. Where the contract is silent, it is a renewal lever: require the buyer’s record key on every billed event.
For vendors · pre-comply

An invoice that passes all seven tests arrives with its evidence

Publish the outcome definition in the order form, including duration, disposition and reopen window.
Emit one event per outcome with a stable ID; emit a negating event for every reversal, cancel or retry.
De-duplicate across channels on the buyer’s contact or ticket key, not your session key; stamp every billed event with the buyer’s record key.
Measure minimums against verified, delivered units; state the basis on the invoice.
Invoice at the contracted rate for the tier in force; show the rate per line.
Give the buyer read access to the event log for the billing period.

Cite as: Floe, Outcome Billing Error Taxonomy v1.1 (2026). Changes are versioned; prior versions remain available. Outcome classes are mutually exclusive in test order T5 → T7 → T2 → T6 → T1. T3 and T4 are invoice-line findings and apply in addition to an outcome’s class.