Raising the defense budget like this is utterly idiotic. The way you're supposed to do it is to look at the kinds of challenges and requirements your military needs and to compare it to what it currently has. Then there should be an examination of what's required to get it from where it is to where you'd want it to be. This should cover everything from R&D to procurement to increasing personnel numbers and so forth. And only then should the government be trying to figure out how much money to spend to make it happen.
What Germany is doing seems to be figuring out the budget increase first, and then trying to justify it afterwards. Unless this is just charity work funnelling money to German defense companies, most of this is going to be a waste of money.