The March numbers for Germany are disappointing, but note that Tesla gets 2000 Euros less per car in Germany - the German EV incentive forces every manufacturer to reduce the price by 2000 Euros per car. (The total incentive is 4000 Euros, 50% from the government and 50% from the manufacturer.) Considering this, Tesla should ship as many Model 3s to other European countries as possible.
While you are quoting the German incentives correctly, I don't think one can draw such a simple conclusion from those numbers.
Tesla has set the price of the Model 3 differently in each of the European country, very likely after having looked at both incentives and what people can be expected to be willing and able to pay.
Tesla's prices are already taking the relevant incentives into account (with the disclaimer that Tesla is not able to guarantee that a given buyer will actually get a given incentive).