I get this question a lot because few months ago, customers were finding that some leggings coming out of Vietnam were cut smaller. This was a problem for a very short while and now this problem has been fixed! Yay! However, people have become sensitive to variations in the leggings which is going to happen due to their handmade nature.
Here is an article with more information!
Though this articles talks about cutting variation, there is going to be other variations causes such as the person sewing it! Just know that each pair is made with care and brings you closer to comfort.