An internal AI service has the same problem as a public cloud: the bill arrives as one number, and the business context is gone by the time finance sees it. Teams that build chargeback take a single provider invoice and turn it into per-team accountability with accurate ROI behind it per this allocation walkthrough. The choice of model determines how much of that accountability the consuming team actually feels.
Token pass-through. You charge each team the metered cost of the model calls it made, plus a markup for platform overhead. It is the most transparent model and the easiest to defend, because every dollar maps to a usage record. It also gives the consuming team a lever: if their prompts are bloated or their agent retries a failing step ten times, they see it in their own invoice. The downside is variance. A team doing exploratory work with long contexts can land a bill that fluctuates wildly month to month, which is hard to plan against.
Seat subscription. Each active user in a consuming team pays a flat monthly fee. Allocating AI spend by seats works well for flat-rate tools like coding assistants or enterprise chat, where the cost driver is seats, not tokens as this cost categorization table shows. The model wins on predictability and simplicity: finance can forecast it, managers can approve it without a usage analyst, and no one argues about decimals. The downside is moral hazard. Heavy users are subsidized by light users, and nobody has a reason to tune a prompt.
Per-task fee. You publish a fixed price per completed automation run: per invoice reconciled, per ticket resolved, per contract clause extracted. It is the cleanest model for anything agentic, because per-task cost is the unit economics of an agent and the direct basis for comparing agent cost against human cost per this guide to cost per task. The fee is stable, the consuming team can budget by volume, and the service's revenue scales with the work delivered. The risk sits on your side: if your 90th-percentile task costs ten times the median, as agent investigations often do, your flat fee can lose money on the tail.
A practical decision rule: if the consuming team can change its own consumption (prompt design, context length, retry policy), charge tokens so the incentive is live. If consumption is roughly one call per user per day, charge seats. If the output has a countable, verifiable finish line that the business already tracks, charge per task.
| Dimension | Token pass-through | Seat subscription | Per-task fee |
|---|---|---|---|
| Cost driver | Input and output tokens per call | Active users | Completed, verified runs |
| Forecast stability for the consumer | Low | High | High |
| Incentive to tune usage | Strong | Weak | Moderate |
| Dispute surface | Token counts and pricing | Who counts as active | Whether a run "completed" |
| Best fit | Custom agents, exploratory work | Flat-rate chat and coding tools | Document, ticket and reconciliation workflows |
| Main risk to the service owner | Low margin on thin markup | Cross-subsidy across users | Losing money on high-variance runs |



