413 seems to be the Air Berlin 375 points * 1,1 silver bonus. This is what the calculator says.
The
Finnair points for that route is 750, so it looks like they decided to pay OP accoring to Air Berlin table, despite ticket being AY code and AB is a oneworld partner. That is pretty shoddy, this is not what they do on other codeshares. AY code means earnings according to AY table.
Also, by looking
here (my bolding) it seems they screwed OP over:
You can also earn points for Finnair codeshare flights operated by our partners. The amount of points depends on your booking class and the distance flown. However, if there is a ticket type in your ticket, points will be granted according to the ticket type percentage and the distance flown.