How does “Measured beats estimated” work on the Carbon Data / ISO Audit page?

A quantity is measured when a document gives it in its own unit — kWh on a bill line, litres on a fuel-card statement, a meter reading — and estimated when only spend is known, converted at a published all-in rate for the year. The two laws are that an actual always replaces an estimate for its month and stream, and that every rate is on the Assumptions tab with its source, confidence and the spend it divides, so a changed rate rescales linearly. Utility spend is split by the account name and the supplier; where the name says heating the electricity call is withheld rather than guessed, because a wrong split is a three-fold error. Spend that cannot be resolved is bucketed and reported, never dropped. Where: Carbon Data / ISO Audit (/accounts/carbon-data).