I think the further along you are, the more unreliable the scans are. I wouldn't stress, just take it as it comes and follow your own instincts on how your body/belly feels. What about your funal height measurements...is this measuring similar to last time?? I had an 11lb 2oz Bubba last time (Scan are so unreliable that the one I had the day before showed him as being 9lbs...they can be wrong either way), and he was 59.5cm long and his birth was very, very easy and uncomplicated, and my DD before him was 9lb. There is plenty of time for things to change too.