How accurate was your 3rd tri growth scan?

Mar • B.S. Mathematics, M.S. Administration. Happily married mom of ID twins with baby #3 on the way
I had one yesterday, 35 weeks, they said baby is 7lbs 8 oz right now, that she will likely be over 10 lbs at my due date. 
Just wondering how accurate other peoples were, if you had one?