The DO228 rating costs are mighty expensive these days. I think when I did the rating on the aircraft with FR Aviation back in 2001, 10hrs, the bond was £10k.
Aero Bildung appear to charge about 3k euroes an hour on the aircraft.
Looking at the costs by the time they have paid for flights, hotels, meals etc as well as the training the 25k euroes might not be far of.