Not a pilot so flame me if needed, (though I did once have a 'flying lesson' but are the A321 landing characteristics so different from the A320? The reason I ask is that the first couple of sectors were on an A320. I would have thought that if they were significantly different then going from A320 to A321 on the same duty could be tricky if you haven't had enough time on type to develop the 'habit' of landing the thing, and if they are subtly different then it would be even more tricky?