But such a simple calculation alone isn’t the right metric. For a start, over the course of a business cycle the exchange rate should move in ways that help to maintain overall balance between demand and supply. In a period of strong demand it will rise, spilling demand abroad by lowering prices for traded goods and services.
The differences seem to be due to the persistent effect of the inflation shock after reunification. For people in East Germany, it contrasted strongly with the norm of zero inflation in the communist era, while West Germans were used to moderate price increases.