Baby Boy measuring big.

Just curious if any of you other momma's have a baby that is measuring big? At 24 weeks he measured 27 weeks and they scheduled me for a growth scan. I had the growth scan December 16th and they said everything looks good and he is in the 80th percentile and for me not to worry. I went back Tuesday, January 3 and at 31 weeks I measured right at 31 weeks and I was scheduled for another growth scan. I do not have gestational diabetes. I am a little worried. Doctor and nurses don't seem to be worried but the term "growth scan" makes me nervous. I just don't see why I need another growth scan if my stomach measured right at 31 weeks. I try to ask questions at the doctors office but I feel like they are not giving me the answers I need. I was just hoping someone else may have experienced this and in fact, it is nothing to worry about.