According to Ewa Michalak you have to consider the shape of your breasts when picking a bra.
UU – most probably the cup indicated by the calculator will be fine;
00 – the cup indicated may fit but you may need a cup size bigger one;
OO – you definitely will need a bigger cup size by one or two cups;
VV – the indicated cup may fit, but you may need a smaller one;
W - the indicated cup will be too big, you’ll need one smaller by 2 or 3 cups;
Source: BFCidade
This makes sense, because after all the tape is measuring only across the center of the breasts, and so the bra size calculator doesn´t take into account the volume of the entire breast.
What do you think of breast shapes & cup sizes ? Do these guidelines hold true for you ? What about the cute Thai poster on the top ?