OK, so the problem here is that I can see base fares and YQ, which is the basis of the calculation, but it's mixed figure for CW out, WTP back, and it isn't sufficient to split it in half for the downgraded sectors - since that would exaggerate the WTP costings.

Do you have - for example - the Finnair email (not Finnair Manage Booking) which in turn gives the fare basis that was used here? Or do you know how much it would have cost you to fly WTP in both directions rather than one?