Is it more common to mistake a boy for a girl or girl for a boy in ultrasound?

Maggi

We were told at 16+1 that we were having a girl during an elective ultrasound and we were hoping on having another ultrasound before we announced (tomorrow) and I'm wondering if it would be more likely for them to tell us girl and it actually be a boy or more likely to tell us boy and it actually be a girl?

I know that all babies have nubs up until a certain point. And I am so nervous to announce tomorrow because our official anatomy scan won't be until march 29th /: but we are having a surprise party for my mother in law that she thinks is a gender reveal so we will be announcing and hoping for the best!