Ultrasounds, while having a reasonable time frame will never have accurate dates. Having said that, I would definately be moving your nuchal fold scan earlier as well as your Dr appt. Just because the nuchal fold test does have to be done during a time frame and pushing to the end will not do. If you are unable to get help from that receptionist, phone you Dr & insist.

My scan dates have always been out. The 2 I had with Matilda put my EDD at 1st June and the 5th of June my LMP put me at the 3rd. Matilda was born on the 17th June. This time my LMP put me around the 28th October, my first scan did too but my second scan put me at 15th October, a huge difference. I'm keeping the first EDD but know that many womens cycles differ and some have a 38 week gestation and others have a 42 week gestation. I wouldn't worry about the scans as far as EDD's go, but as far as the nuchal fold I would definately push for it to be done a week sooner.