To answer your question - yes this can happen where one is significantly larger than the other and it's up to you if you ever wanted to fix this or just wear more padding. Your numbers confuse me a bit though because the actual number refers to the rib cage circumference, but the cup lettering is the actual size of the breast. So hypothetically a woman with a different breast size would still have, lets say a 36 rib cage but one being 36 C and the other breast being a 36 B. It happens though.