Since the irrevocably fixed conversion rates are crooked numbers, they will normally not convert exactly. But for customers to be able to retrain their feel for prices, they need the help of retailers and banks in the form of a dual display of prices.
In surveys, consumers have repeatedly voiced concern that the changeover to the new currency will be taken as an opportunity by retailers to raise prices. This holds true for the popular signal prices like DM0.49 or DM1.99, for example, by which a clean price threshold is avoided. Owing to the crooked conversion rate, the conversion will result in crooked prices.