AGR Cooler Control: Audi 2.7 TDI Questions

I have always believed that the diverter valve of the AGR cooler has the following function:
Direct bypass of hot exhaust gases when the engine is cold, followed by switching the path through the EGR cooler to cool the exhaust gases.

I've now noticed that whenever a friend accelerates, the valve for the EGR cooler is activated and switches. However, I can't tell whether the cooler is opening or closing.

Why?