Since you are comparing a sum total of a set of zones (or fills, not sure which it is) to another single one, I don't think this calculation can be done with properties. Since properties are set for a single element.
We do these sort of calculations in Excel, since we need to derive a lot more calculations from the square meters of a project. That does mean manually typing in the values in excel initially, but even with large appartment projects that rarely means more than a few stories and appartment types.
You can also add dummy text fields to schedules where you can just type values if you don't like adding the text to layout.
Erwin Edel, Project Lead, Leloup Architectenwww.leloup.nl
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