I think you have uncovered a bug in the Finnair website. The website indeed marks those AY-coded AB-operated flights as sold under Finnair ticket types. However the fare basis is NTOUR2SE. For value tickets, the fare basis is normally bVAcc2 or bHVAcc2 where b is the booking class and cc is the country code (H is for peak season).

I would file a complaint to the customer service, since the Finnair website is clearly misleading, or even plain wrong here.