How does ESG by ZYT actually calculate a figure?

The sequence for a single entry:

• Convert the quantity to the factor’s unit — litres to litres, kWh to kWh — refusing rather than guessing if the units cannot be reconciled.
• Resolve a factor for the activity, country, region and year, preferring an exact regional match and falling back through nearest-earlier vintage, then country, then global default.
• Record how good that match was, and warn where the factor is older or newer than the reporting year.
• Multiply, and write the result together with a snapshot of the factor value, its tier and the resolution path.

For grid electricity, waste and water the fallback chain stops early and deliberately. These model a process that differs by country, so if no factor exists for your country the software declines to produce a number and records an exclusion with the reason. It does not borrow a neighbour’s factor.

Recalculating after a registry change is an explicit, logged action. Figures do not silently move underneath a report you have already sent to a customer.