Can someone enlighten you whether the Avios change or cancellation fee will have to be paid per Booking, per Passenger, or per Passenger per Segment?

As an example, let's say I booked DUS-LHR-MIA-LHR-DUS for 4 Adults, 1 Child and 1 Infant, but need to cancel the journey, or simply change the outbound flights.

How much would that set me back? As far as I understand it (I don't), it could be anything between €42.50 (fee for booking) or €1020 (€42.50 x 6 Pax x 4 Segments)

So quite a big gap....

Any experiences to share?

Thanks
raph