I think it has to do with the tuning for the new emissions testing method.
During a conversation with my dealer (about a rather steep price-hike for the Plus 4 recently) he said that they had to reduce NOX emissions due to new regulations, which led to higher CO2 emissions.
Therefore the Plus 4 has significantly risen in price since last year in the Netherlands, since new-car taxing is CO2 emission based over here.
