@jon I've seen a similar price difference when I went to Paris in February: the Antwerp-Paris price was twice the Rotterdam-Paris price on the exact same train. It was well worth the extra 30 minute travel time (also with 5tph to Rotterdam and 1tph to Antwerp, the stress/risk of missing the connection is much lower and ICNG is nicer than i11 with heavy luggage). Also (but this might be a coincidence), we never got the cramped tail end of coach 18 seats the times we booked via Rotterdam.