Go ahead and get the larger size in the leggings!
I used the size chart to buy a pair of leggings, but they almost required the jaws of life to get them back off of me. I contacted customer service about sending them back for a larger pair, and instead...they sent me a larger pair and told me not to send back the medium pair. I sent it to my nurse practitioner sister who is 20 pounds lighter, and she could barely fit them either. She's giving them to her 20-year-old daughter.