I don't get hung up on this, just need it to fit, but I am lucky not to worry about weight! I swear, when I was younger, like 18-20yrs old, I was a 10-12 weighing less than I do now wearing size 8. You don't get bigger or smaller with the size on the label! I think they must adjust the sizing to that of the "average" American woman. In Europe, I usually take about the equivalent of the US 12 for it to fit!

Just buy what you like and what you feel good wearing!