Stock levels as delta rows in DAX / BISM Tabular

A common way to compress large amounts of snap shot data is to store delta values instead of each snapshot value. This makes sense, if the data does not change every day. But for a good query performance you might not want to aggregate data over long periods.Therefore it makes sense to have a regular absolute snapshot value in the data and to use deltas between those snapshots. The work needed to create the periodic snapshots is usually done in the ETL process.