Bravado question!

I'm looking into purchasing a bravado brand nursing bra and measured according to their guidelines and the band size is 2 sizes bigger than I'm currently wearing. Has anyone else had this and the size be correct? I'm currently wearing a 34D VS bra on the center clasp but the bravado measurement put me in a 38C. I've tried their live chat and have been waiting for 40 minutes for a response...and I'd like to purchase today to take advantage of their 15% off. Thanks in advance!!