I don't see any signs that this takes business deals into account: volume pricing that covers other products (Sony makes many other products that use similar parts), cross-promotion (getting paid to ship specific demos or software), etc.
As for volume pricing it almost certainly does take that into account. Most electronic component manufacturers publish "Budgetary price per xK pcs" which I assume is where most of prices mentioned in article come from. For even slightly specialized parts this number tends to be significantly lower (tens of percent to order of magnitude for some parts) than price given by distributor even for same xK volume discount. Also most significant parts that are used across different Sony products tend to be either insignificant (passives) or manufactured by Sony (or semi-custom parts manufactured for Sony).
I doubt there are published prices on the web for the volumes that Sony is buying. Much smaller companies than Sony make special deals with suppliers for parts.