Token Accounting Drift: When Your Trace Logs Don't Match the Provider Invoice
There is a finance meeting that happens at every company shipping a hosted LLM feature, usually around month four. The engineering team has been logging token counts from every request. The finance team has the provider's invoice. The numbers don't agree. Sometimes the gap is five percent. Sometimes it is thirty. The engineers say the invoice is wrong. The finance team says the logs are wrong. Both teams are technically correct, and neither owns the reconciliation.
The drift is not fraud. It is a structural measurement problem, and the structure has at least six independent failure modes that compound. A team that does not own those failure modes will spend the next quarter writing apology emails to FP&A about why the forecast slipped, when the real story is that nobody on the engineering side ever audited what "token" meant in their own logs.
