Question:when measuring for band size,is it usually done above or below the breasts?I've been looking online and some sites say above and some say below,so not sure which is correct.

I am tired of bras not fitting well and being so uncomfortable and read how 80% of women are wearing the wrong size bra.So I took my measurements and put them in an online calculator(measuring below breasts for band size) and was shocked for the results to be 34F or 34 FF.I've always worn a 34D or 34DD.That's a big difference!

Also,if it's a half number when measuring,should I round up or down?