View-relative LOD: the expression evaluates at (the chart’s grouping plus the listed dimensions) — a finer grain — and the chart’s field-well aggregation re-aggregates the values back to the view. Drop Include(Customer.Id, [Revenue]) on a by-region chart with agg avg for “average per-customer revenue per region” without naming the region anywhere.
Unlike Fixed, the grain follows the chart: change the grouping and the LOD moves with it.
Per-entity averages that should adapt to whatever the viewer groups by — avg per-customer revenue per region today, per segment tomorrow, same measure.
When you’d otherwise re-create several Fixed measures for different chart grains.