the Scope software will find all cards in the system and adress them as one unit.
There is no independant control of the cards, so the version 4 will see both, as will the version 4.5.
In earlier system versions it seemed Scope tried to 'replace' a missing S/TDM cable by communication over the PCI slot, which was a total performance breakdown (and useless).
In the current version it more or less stops with an error message about 'missing STDM connection' (I haven't verified that, tho)
The devices are registered to ONE card's serial number, it doesn't matter which card or where it's positioned as long as the card is present. In this context a card acts as a mega dongle (a very convenient one btw).
I've registered all my devices on one card and another one (which is not even registered at all) just acts as a DSP (and IO) extension.
In other cases it may be more convenient to register to several cards if they are supposed to be used in different PCs, for example one for recording apps and one as synth extension.
Anyway, if the cards are in one system all DSPs and IO ports are useable as if it was a single big system - it's really easy
cheer, Tom