Heard from customer service today.
They maintain that I will only earn 25% for the flight in question, but will compensate me with 1000 points (so the flight will get me 400 + 1000 instead of 1600) for the ... misunderstanding ?
They also remind me to ask to be booked on the operation carriers flightnumber when I book over the phone in the future. This whole 25% thing is getting very complicated ...
Cheers