Seat Cost Per Deliverable

Seat cost per deliverable measures what an agency actually pays for each unit of client work produced on a frontier assistant, not what the subscription line item says. A $30 seat looks cheap until three people touch the same retainer deliverable and the true cost lands at $90 plus review time. The framework forces a simple calculation: monthly seat spend divided by completed, client-accepted deliverables, tracked per role. It matters because model releases reset the math every few months. OpenAI's October 2, 2026 GPT-6 guide splits the family into three tiers for prototyping, feature development, and multi-step workflow orchestration, and routing a job to the wrong tier inflates cost without improving the output a client sees. Agencies that track this ratio can move copy work to a cheaper tier, keep orchestration on the expensive one, and defend retainer margin when a client asks why the AI line item grew.