After several years of my wife struggling to find a properly fitting bra (with several "professional" fittings) I decided to research it myself, found this community, and was able to help her fine a bra that fits properly. Highly recommended.
Most bra stores simply don't carry larger bra sizes, and will "fit" you into whatever they happen to carry and want to sell you.
is the product of a community (with the same name) on reddit