If X2 includes all the features of Expanded, so that the entire range is narrowed down to just Producer, Stdio & Expanded, then it's logical to assume there will be different pricing options depending on what you already have
e.g. $99 for Expanded customers, $149 for Producer, something along those lines
I'm guessing that any of the optional PC modules which you might have purcahsed will have to be installed separately, by the user, post-install as there's no way on earth they could work out a pricing strategy for the large number of possible combinations.
Just my thoughts.