Euro comparispn: flying LH on AMS-FRA-SFO 2 or 3 yrs ago. Ticket was a LH oz - Euro - oz Biz Z fare. Suffered an Invol downgrade on the short AMS-FRA sector in paid Z (discount Business) to economy on same plane. Immediately offered E200 compensation voucher for encashment at FRA during tranfer stop. Money duely handed over after about half an hour of stuffing around because tbey couldn't find the key to the cash tin hidden under a countet.