I can't remember with DS1 as that was over 12 years ago but he was born 7lb 8 and he was 11 days over due .With DS2 I was always measuring 2-4 wks/cm more and he was born 9lb 7 but he was also 11 days over due so he had more time to grow bigger.
The same thing happened with the next 3, I was always measuring bigger than what I was but they were born, 8lb 5.5, 8lb and 8lb 9 and they were all overdue.
The only time I measured small was when the person doing the measuring made a mistake.
I don't believe that if you measure big then you will have a big baby.
I agree with Ryn, it is a stupid way to tell the size of a baby.
Take care
Michelle