Wow Maya, what an incredibly useful and amazing post!
You got me to remeasure myself and I think I might be in the wrong size ( sigh...). After thinking for the most of my adult life to be 34A 2 years ago I was fitted at Nordies to be 32C and was quite happy with those bras. I have just measured myself and my underbust measurement is 29" ! That means that I need a band size of 30, right? And that I (gasp) might actually need a 30D! I can not even imagine that, I am still in the mind set of being an A cup... No Intimacy here, but I will be going to Boston soon so I will have to go for another fitting.
Btw, where on those site were the photos of women going from 34A to 30D ( which might be case)? Couldn't find them, and it seems that it would be helpful.