It is of course not the 500 between Ams and CDG I am worried about but the 11,000 between Ams and JNB. Technically, I haven't flown the ticket I booked. If I had let the first segment drop, they would have cancelled the whole ticket and made me buy a new one. They can't do that if I drop the last segment but my concern is that it will effect the miles on the flights I actually took.